Transition Metal-Mediated Ring Construction: The Yu Synthesis of 1-Desoxyhypnophilin

State University ◽

Enantiomerically Pure ◽

Quaternary Centers ◽

University Of Oxford ◽

National University ◽

Cu Catalyst ◽

Both 1 and 3 are inexpensive prochiral starting materials. Tae-Jong Kim of Kyungpook National University devised (Organomet. 2008, 27, 1026) a chiral Cu catalyst that efficiently converted 1 (other ring sizes worked as well) to the enantiomerically pure ester 2. Alexandre Alexakis of the University of Geneva found (Adv. Synth. Cat. 2008, 350, 1090) a chiral Cu catalyst that mediated the enantioselective coupling of 3 with Grignard reagents such as 4 . The π-allyl Pd complex derived from 6 is also prochiral. Barry M. Trost of Stanford University showed (Angew. Chem. Int. Ed. 2008, 47, 3759) that with appropriate ligand substitution, coupling with the phthalimide 7 proceeded to give 8, readily convertible to (-)-oseltamivir (Tamiflu) 9, in high ee. Jonathan W. Burton of the University of Oxford found (Chem Commun. 2008, 2559) that Mn(OAc)3 -mediated cyclization of 10 delivered the lactone 12 with high diastereocontrol. John Montgomery of the University of Michigan observed (Organic Lett. 2008, 10, 811) that the Ni-catalyzed cyclization of 12 also proceeded with high diastereocontrol. Ken Tanaka of the Tokyo University of Agriculture and Technology combined (Angew. Chem. Int. Ed. 2008, 47, 1312) Rh-catalyzed ene-yne cyclization of 14 with catalytic ortho C-H functionalization, leading to 16 in high ee. Eric N. Jacobsen of Harvard University designed (Angew. Chem. Int. Ed. 2008, 47, 1469) a chiral Cr catalyst for the intramolecular carbonyl ene reaction, that converted 17 to 18 in high ee. Using a stoichiometric prochiral Cr carbene complex 20 and the enantiomerically-pure secondary propargylic ether 19, Willam D. Wulff of Michigan State University prepared (J. Am. Chem. Soc. 2008, 130, 2898) a facially-selective Cr-complexed o -quinone methide intermediate, that cyclized to 21 with high ee. A variety of methods have been put forward for the transition metal-mediated construction of polycarbocyclic systems. One of the more powerful is the enantioselective Rh-catalyzed stitching of the simple substrate 22 into the tricycle 23 devised (J. Am. Chem. Soc. 2008, 130, 3451) by Takanori Shibata of Waseda University. Inter alia, ozonolysis of 23 delivered the cyclopentane 24 containing two all-carbon quaternary centers.

Reviewer Acknowledgements

Journal of Education and Training Studies ◽

10.11114/jets.v6i1.2908 ◽

2017 ◽

Vol 6 (1) ◽

pp. 169

Author(s):

Robert Smith

Keyword(s):

Education And Training ◽

Economic Research ◽

State University ◽

American University ◽

Kwazulu Natal ◽

National University ◽

The University ◽

And Training

Journal of Education and Training Studies (JETS) would like to acknowledge the following reviewers for their assistance with peer review of manuscripts for this issue. Many authors, regardless of whether JETS publishes their work, appreciate the helpful feedback provided by the reviewers. Their comments and suggestions were of great help to the authors in improving the quality of their papers. Each of the reviewers listed below returned at least one review for this issue.Reviewers for Volume 6, Number 1Brenda L. Shook, National University, USACagla Atmaca, Pamukkale University, TurkeyCarole Fern Todhunter, The University of Nottingham, UKCharlotte Alverson, University of Oregon, USAChosang Tendhar, Long Island University (LIU), USAEnisa Mede, Bahcesehir University, TurkeyErica D. Shifflet-Chila, Michigan State University, USAGreg Rickwood, Nipissing University, CanadaHyesoo Yoo, Virginia Tech., USAIoannis Syrmpas, University of Thessaly, GreeceJohn Cowan, Edinburgh Napier University, UKLinda J. Rappel, Yorkville University/University of Calgary, CanadaMan-fung Lo, The Hong Kong Polytechnic University, Hong KongMassimiliano Barattucci, Ecampus University, ItalyMaurizio Sajeva, Pellervo Economic Research PTT, FinlandMehmet Inan, Marmara University, TurkeyMichail Kalogiannakis, University of Crete, GreeceMin Gui, Wuhan University, ChinaNerina Fernanda Sarthou, Universidad Nacional del Centro de la Provincia de Buenos Aires, ArgentinaPirkko Siklander, University of Lapland, FinlandRichard H. Martin, Mercer University, USARichard Penny, University of Washington Bothell, USARiyadh Tariq Kadhim Al-Ameedi, Babylon University, IraqRufaidah Kamal Abdulmajeed, Baghdad University, IraqSadia Batool, Preston University Islamabad, PakistanSelloane Pitikoe, University of Kwazulu-Natal, South AfricaSenem Seda Şahenk Erkan, Marmara University, TurkeySeyyedeh Mina Hamedi, Ferdowsi University of Mashhad, IranSisi Chen, American University of Health Sciences, USATilanka Chandrasekera, Oklahoma State University, USAYalçın Dilekli, Aksaray University, TurkeyYerlan Seisenbekov, Kazakh National Pedagogical University, KazakhstanYi Lu, American Institute for Research, USAYuChun Chen, Louisiana Tech University, USARobert SmithEditorial AssistantOn behalf of,The Editorial Board of Journal of Education and Training StudiesRedfame Publishing9450 SW Gemini Dr. #99416Beaverton, OR 97008, USAURL: http://jets.redfame.com

Organic Functional Group Protection and Deprotection

Organic Synthesis ◽

10.1093/oso/9780190646165.003.0013 ◽

2017 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Environmental Science ◽

Reduction Product ◽

State University ◽

University Of Pittsburgh ◽

Fe Catalyst ◽

Wide Range ◽

Cu Catalyst ◽

Simple Extraction ◽

Martin Oestreich of the Technische Universität Berlin developed (Eur. J. Org. Chem. 2014, 2077) the Birch reduction product 2 as a donor for the silylation of an alcohol 1 to give 3. Atahualpa Pinto of the SUNY College of Environmental Science and Forestry devised (Tetrahedron Lett. 2014, 55, 2600) conditions for the monosilylation of the diol 4 to give 5. Quanxuan Zhang of Michigan State University reported (Tetrahedron Lett. 2014, 55, 3384) the preparation (not illustrated) of the mono-THP ethers of symmetrical diols. The product from the Mitsunobu coupling of an acid with an alcohol 6 can be difficult to purify. Takashi Sugimura of the University of Hyogo showed (Synthesis 2013, 45, 931) that the oxidation product from 7 and the reduction product from 8 could both be removed from the product 9 by simple extraction. David Milstein of the Weizmann Institute of Science found (Angew. Chem. Int. Ed. 2014, 53, 4685) that an Fe catalyst could be used to reduce the trifluoroacetate 10 to 11. Jean-Michel Vatèle of the Université Lyon 1 oxidized (Synlett 2014, 25, 115) the benzylidene acetal 12 selectively to the monobenzoate 13. Xinyu Liu of the University of Pittsburgh organized (Chem. Commun. 2014, 50, 3155) a family of acid-sensitive esters that can be selectively removed in the presence of other esters, as exemplified by the conversion of 14 to 15. Ryo Yazaki and Takashi Ohshima of Kyushu University observed (Angew. Chem. Int. Ed. 2014, 53, 1611) that an amine would add spontaneously to acrylonitrile 17 to give 18. In the presence of a Cu catalyst, alcohols added to 17 even more readily, allowing the preparation of 18 from 16. Diego Gamba-Sánchez of the Universidad de los Andes used (J. Org. Chem. 2014, 79, 4544) simple Fe catalysts to activate a wide range of amides, including 20, to become acylating agents, converting 19 to 21. 1,2-Addition to t-butylsulfanylimines is widely used to construct aminated stereogenic centers. Xiaodong Yang and Hongbin Zhang of Yunnan University established (Chem. Commun. 2014, 50, 6259) a general protocol for cleaving the N–S bond in the product 22 to give the desired free amine 23.

Enantioselective Synthesis of Alcohols and Amines: The Ichikawa Synthesis of (+)-Geranyllinaloisocyanide

Organic Synthesis ◽

10.1093/oso/9780190200794.003.0034 ◽

2015 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Allylic Alcohol ◽

Florida State University ◽

State University ◽

Quaternary Amine ◽

National University ◽

Cu Catalyst ◽

Enantioselective Addition ◽

Institute Of Technology ◽

The University ◽

University Of Manchester

Shuichi Nakamura of the Nagoya Institute of Technology reduced (Angew. Chem. Int. Ed. 2011, 50, 2249) the α-oxo ester 1 to 2 with high ee. Günter Helmchen of the Universität-Heidelberg optimized (J. Am. Chem. Soc. 2011, 133, 2072) the Ir*-catalyzed rearrangement of 3 to the allylic alcohol 4. D. Tyler McQuade of Florida State University effected (J. Am. Chem. Soc. 2011, 133, 2410) the enantioselective allylic substitution of 5 to give the secondary allyl boronate, which was then oxidized to 6. Kazuaki Kudo of the University of Tokyo developed (Org. Lett. 2011, 13, 3498) the tandem oxidation of the aldehyde 7 to the α-alkoxy acid 8. Takashi Ooi of Nagoya University prepared (Synlett 2011, 1265) the secondary amine 10 by the enantioselective addition of an aniline to the nitroalkene 9. Yixin Lu of the National University of Singapore assembled (Org. Lett. 2011, 13, 2638) the α-quaternary amine 13 by the addition of the aldehyde 11 to the azodicarboxylate 10. Chan-Mo Yu of Sungkyunkwan University added (Chem. Commun. 2011, 47, 3811) the enantiomerically pure 2-borylbutadiene 15 to the aldehyde 14 to give 16 in high ee. Because the allene is readily dragged out to the terminal alkyne, this is also a protocol for the enantioselective homopropargylation of an aldehyde. Lin Pu of the University of Virginia devised (Angew. Chem. Int. Ed. 2011, 50, 2368) a protocol for the enantioselective addition of 17 to the aldehyde 18 to give 19. Xiaoming Feng of Sichuan University developed (Angew. Chem. Int. Ed. 2011, 50, 2573) a Mg catalyst for the enantioselective addition of 21 to the α-oxo ester 20. Tomonori Misaka and Takashi Sugimura of the University of Hyogo added (J. Am. Chem. Soc. 2011, 133, 5695) 23 to 24 to give the Z-amide 25 in high ee. Marc L. Snapper and Amir H. Hoveyda of Boston College developed (J. Am. Chem. Soc. 2011, 133, 3332) a Cu catalyst for the enantioselective allylation of the imine 26. Jonathan Clayden of the University of Manchester effected (Org. Lett. 2010, 12, 5442) the enantioselective rearrangement of the amide 29 to the α-quaternary amine 30.

C-O Ring Natural Products: (-)-Serotobenine (Fukuyama-Kan), (-)-Aureonitol (Cox), Salmochelin SX (Gagné), Botcinin F (Shiina), (-)-Saliniketal B (Paterson), Haterumalide NA (Borhan)

Organic Synthesis ◽

10.1093/oso/9780199764549.003.0051 ◽

2011 ◽

Author(s):

Douglass Taber

Keyword(s):

Indole Alkaloid ◽

Chiral Auxiliary ◽

State University ◽

Ene Reaction ◽

Enantiomerically Pure ◽

Cambridge University ◽

Stereogenic Centers ◽

Ready Access ◽

Tohru Fukuyama of the University of Tokyo and Toshiyuki Kan of the University of Shizuoka devised ( J. Am. Chem. Soc. 2008, 130, 16854) the chiral auxiliary-directed Rh-mediated cyclization of 1, setting the two stereogenic centers of 2 with high stereocontrol. The ester 2 was carried on to the indole alkaloid (-)-Serotobenine 3. In the course of a synthesis of (-)-Aureonitol 6, Liam R. Cox of the University of Birmingham developed (J. Org. Chem. 2008, 73, 7616) the diastereoselective intramolecular addition of an allyl silane 4 to give the tetrahydrofuran 5. In analogy to what is known about the intramolecular ene reaction, the diastereocontrol observed for this cyclization may depend on the allyl silane being Z. Michel R. Gagné of the University of North Carolina found (J. Am. Chem. Soc. 2008, 130, 12177) that the Ni-catalyzed coupling of organozinc halides could be extended to glycosyl halides such as 7. This opened ready access to C -alkyl and C -aryl glycosides, including Salmochelin SX 10. Isamu Shiina of the Tokyo University of Science established (Organic Lett. 2008, 10, 3153) that the acid-mediated cyclization of the Sharpless-derived epoxide 10 proceeded with clean inversion, to give 11. The highly-substituted tetrahydropyran core 11 was then elaborated to the antifungal Botcinin F 12. Ian Paterson of Cambridge University optimized (Organic Lett. 2008, 10, 3295) the Pd-catalyzed spirocyclization of the ene diol 13, leading to 14, the enantiomerically-pure bicyclic core of (-)-Saliniketal B 15. Haterumalide NA 18 presented the particular challenge of assembling the geometrically-defined chloroalkene, in addition to closing the macrolide ring. Babak Borhan of Michigan State University addressed (J. Am. Chem. Soc. 2008, 130, 12228) both of these challenges together, electing to employ a chlorovinylidene chromium carbenoid, as developed by Falck and Mioskowski, to effect the macrocyclization of 16 to 17.

Best Synthetic Methods: Reduction

Organic Synthesis ◽

10.1093/oso/9780199764549.003.0006 ◽

2011 ◽

Author(s):

Douglass Taber

Keyword(s):

Direct Reduction ◽

Synthetic Methods ◽

Cancer Center ◽

State University ◽

University Of Texas ◽

Ru Catalyst ◽

Reaction Matrix ◽

National University ◽

Jaiwook Park of Pohang University of Science and Technology has developed (Org. Lett. 2007, 9, 3417) a procedure for the preparation of Pd-impregnated magnetic Fe nanoparticles. This effective hydrogenation catalyst was attracted to an external magnet and so was easily separated from the reaction matrix. Duk Keun An of Kangwon National University has found (Chem. Lett. 2007, 36, 886) that by including NaOtBu, Dibal reduction of an ester such as 3 can be made to reliably stop at the aldehyde 4. By using the easily-prepared pentaﬂurophenyl ester 5, Panagiota Moutevelis-Minakakis of the University of Athens was able to reduce an acid to the alcohol 6. Lionel A. Saudan of Firmenich SA, Geneva has devised (Angew. Chem. Int. Ed. 2007, 46, 7473) a Ru catalyst that will hydrogenate an ester such as 7 to the alcohol 8 without reducing an internal alkene. Norio Sakai of the Tokyo University of Science has established (J. Org. Chem. 2007, 72, 5920) what promises to be a general route to ethers 10, by direct reduction of the corresponding ester 9. Hideo Nagashima of Kyushu University has developed ( Chem. Commun. 2007, 4916) a Ru catalyst that effected selective hydrogenation of an amide 11 to the amine 12 without reducing ketones or esters. Alternatively, Jason S. Tedrow of Amgen Inc., Thousand Oaks, CA has found (J. Org. Chem. 2007, 72, 8870) that a protocol developed by Robert E. Maleczka, Jr. of Michigan State University was effective for reducing an aryl ketone 13 to the corresponding hydrocarbon 14 without reducing the amide. The stereocontrolled reductive amination of cyclic ketones such as 15 has been a continuing challenge. Shawn Cabral of Pfizer, Inc. in Groton, CT has reported (Tetrahedron Lett. 2007, 48, 7134) complementary reagent combinations, leading selectively to either 16 or 17. To control catalytic hydrogenation, it is often desirable to control the H2 supply. John S. McMurray of the University of Texas M. D. Anderson Cancer Center in Houston has shown (J. Org. Chem. 2007, 72, 6599) that Et3SiH is a convenient H2 source. Nitro alkanes add to aldehydes to give nitro alkenes such as 20.

Arrays of Stereogenic Centers: The Davies Synthesis of Acosamine

Organic Synthesis ◽

10.1093/oso/9780190200794.003.0041 ◽

2015 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Conjugate Addition ◽

State University ◽

One Pot ◽

Relative Configuration ◽

University Of Texas ◽

Stereogenic Centers ◽

National University ◽

The University ◽

Mediated Oxidation

Babak Borhan of Michigan State University found (Angew. Chem. Int. Ed. 2011, 50, 2593) that the ligand developed for asymmetric osmylation worked well for the enantioselective cyclization of 1 to 2. Kyungsoo Oh of IUPUI devised (Org. Lett. 2011, 13, 1306) a Co catalyst for the stereocontrolled addition of 4 to 3 to give 5. Michael J. Krische of the University of Texas Austin prepared (Angew. Chem. Int. Ed. 2011, 50, 3493) 8 by Ir*-mediated oxidation/addition of 7 to 6. Yixin Lu of the National University of Singapore employed (Angew. Chem. Int. Ed. 2011, 50, 1861) an organocatalyst to effect the stereocontrolled addition of 10 to 9. Naoya Kumagai and Masakatsu Shibasaki of the Institute of Microbial Chemistry, Tokyo took advantage (J. Am. Chem. Soc. 2011, 133, 5554) of the soft Lewis basicity of 13 to effect stereocontrolled condensation with 12. Yujiro Hayashi of the Tokyo University of Science found (Angew. Chem. Int. Ed. 2011, 50, 2804, not illustrated) that aqueous chloroacetaldehyde participated well in crossed aldol condensations. Andrew V. Malkov, now at Loughborough University, and Pavel Kocovsky of the University of Glasgow showed (J. Org. Chem. 2011, 76, 4800) that the inexpensive mixed crotyl silane 16 could be added to 15 with high stereocontrol. Shigeki Matsunaga of the University of Tokyo and Professor Shibasaki opened (J. Am. Chem. Soc. 2011, 133, 5791) the meso aziridine 18 with malonate 19 to give 20. Masahiro Terada of Tohoku University effected (Org. Lett. 2011, 13, 2026) the conjugate addition of 22 to 21 with high stereocontrol. Jinxing Ye of the East China University of Science and Technology reported (Angew. Chem. Int. Ed. 2011, 50, 3232, not illustrated) a related conjugate addition. Kian L. Tian of Boston College observed (Org. Lett. 2011, 13, 2686) that the kinetic hydroformylation of 24 set the relative configuration of two stereogenic centers. Alexandre Alexakis and Clément Mazet of the Université de Genève established (Angew. Chem. Int. Ed. 2011, 50, 2354) a tandem one-pot procedure for the addition of 26 to 27 to give 28.

Transition Metal-Mediated Construction of Carbocycles: Dimethyl Gloiosiphone A (Takahashi), Pasteurestin A (Mulzer), and Pentalenene (Fox)

Organic Synthesis ◽

10.1093/oso/9780199764549.003.0074 ◽

2011 ◽

Author(s):

Douglass Taber

Keyword(s):

Transition Metal ◽

South Florida ◽

Health Science ◽

Pt Catalyst ◽

Max Planck ◽

Au Catalyst ◽

Ru Catalyst ◽

National University ◽

Rh Catalyst ◽

There continue to be new developments in transition metal- and lanthanide-mediated construction of carbocycles. Although a great deal has been published on the asymmetric cyclopropanation of styrene, relatively little had been reported for other classes of alkenes. Tae-Jeong Kim of Kyungpook National University has devised (Tetrahedron Lett. 2007, 48, 8014) a Ru catalyst for the cyclopropanation of simple α-olefins such as 1. X. Peter Zhang of the University of South Florida has developed (J. Am.Chem. Soc. 2007, 129, 12074) a Co catalyst for the cyclopropanation of alkenes such as 5 having electron-withdrawing groups. Alexandre Alexakis of the Université de Genève has reported(Angew. Chem. Int. Ed. 2007, 46, 7462) simple monophosphine ligands that enabled enantioselective conjugate addition to prochiral enones, even difficult substrates such as 8. Seunghoon Shin of Hanyang University has found (Organic Lett. 2007, 9, 3539) an Au catalyst that effected the diastereoselective cyclization of 10 to the cyclohexene 11, and Radomir N. Saicic of the University of Belgrade has carried out (Organic Lett. 2007, 9, 5063), via transient enamine formation, the diastereoselective cyclization of 12 to the cyclohexane 13. Alois Fürstner of the Max-Planck- Institut, Mülheim has devised (J. Am. Chem. Soc. 2007, 129, 14836) a Rh catalyst that cyclized the aldehyde 14 to the cycloheptenone 15. Some of the most exciting investigations reported in recent months have been directed toward the direct diastereo- and enantioselective preparation of polycarbocyclic products. Rai-Shung Liu of National Tsing-Hua University has extended (J. Org. Chem. 2007, 72, 567) the intramolecular Pauson-Khand cyclization to the epoxy enyne 16, leading to the 5-5 product 17. Michel R. Gagné of the University of North Carolina has devised (J. Am. Chem. Soc. 2007, 129, 11880) a Pt catalyst that smoothly cyclized the polyene 18 to the 6-6 product 19. Yoshihiro Sato of Hokkaido University and Miwako Mori of the Health Science University of Hokkaido have described (J. Am. Chem. Soc. 2007, 129, 7730) a Ru catalyst for the cyclization of 20 to the 5-6-5 product 21. Each of these processes proceeded with high diastereocontrol.

New Methods for C-N Ring Construction

Organic Synthesis ◽

10.1093/oso/9780199764549.003.0055 ◽

2011 ◽

Author(s):

Douglass Taber

Keyword(s):

New York ◽

Gold Complex ◽

Cascade Process ◽

State University ◽

University Of Alberta ◽

Cornell University ◽

University Of New Mexico ◽

Memory Of Chirality ◽

Cu Catalyst ◽

Chaozhong Li of the Shanghai Institute of Organic Chemistry demonstrated (Organic Lett. 2008, 10, 4037) facile and selective Cu-catalyzed β-lactam formation, converting 1 to 2. Paul Helquist of the University of Notre Dame devised (Organic Lett. 2008, 10, 3903) an effective catalyst for intramolecular alkyne hydroamination, converting 3 into the imine 4. Six-membered ring construction worked well also. Jon T. Njardarson of Cornell University found (Organic Lett. 2008, 10, 5023) a Cu catalyst for the rearrangement of alkenyl aziridines such as 5 to the pyrroline 6. Philippe Karoyan of the UPMC, Paris developed (J. Org. Chem. 2008, 73, 6706) an interesting chiral auxiliary directed cascade process, converting the simple precursor 7 into the complex pyrrolidine 9. Sherry R. Chemler of the State University of New York, Buffalo devised (J. Am. Chem. Soc. 2008, 130, 17638) a chiral Cu catalyst for the cyclization of 10, to give 12 with substantial enantiocontrol. Wei Wang of the University of New Mexico demonstrated (Chem. Commun. 2008, 5636) the organocatalyzed condensation of 13 and 14 to give 16 with high enantio- and diastereocontrol. Two complementary routes to azepines/azepinones have appeared. F. Dean Toste of the University of California, Berkeley showed (J. Am. Chem. Soc. 2008, 130, 9244) that a gold complex catalyzed the condensation of 17 and 18 to give 19. Frederick G. West of the University of Alberta found (Organic Lett. 2008, 10, 3985) that lactams such as 20 could be ring-expanded by the addition of the propiolate anion 21. Takeo Kawabata of Kyoto University extended (Organic Lett . 2008, 10, 3883) “memory of chirality” studies to the cyclization of 23, demonstrating that 24 was formed in high ee. Paul V. Murphy of University College Dublin took advantage (Organic Lett . 2008, 10, 3777) of the well-known intramolecular addition of azides to alkenes, showing that the intermediate could be intercepted with nucleophiles such as thiophenol, to give the cyclized product 26 with high diastereocontrol.

C-O Ring Containing Natural Products: Paeonilactone B (Taylor), Deoxymonate B (de la Pradilla), Sanguiin H-5 (Spring), Solandelactone A (White), Spirastrellolide A (Paterson)

Organic Synthesis ◽

10.1093/oso/9780199764549.003.0050 ◽

2011 ◽

Author(s):

Douglass Taber

Keyword(s):

Oxidative Coupling ◽

Claisen Rearrangement ◽

Cyclic Carbonate ◽

Membered Ring ◽

State University ◽

Enantiomerically Pure ◽

University Of Cambridge ◽

Spirastrellolide A ◽

The University ◽

Oregon State University

Richard J. K. Taylor of the University of York has developed (Angew. Chem. Int. Ed. 2008, 47, 1935) the diasteroselective intramolecular Michael cyclization of phosphonates such as 2. Quenching of the cyclized product with paraformaldehyde delivered ( + )-Paeonilactone B 3. Roberto Fernández de la Pradilla of the CSIC, Madrid established (Tetrahedron Lett. 2008, 49, 4167) the diastereoselective intramolecular hetero Michael addition of alcohols to enantiomerically-pure acyclic sulfoxides such as 4 to give the allylic sulfoxide 5. Mislow-Evans rearrangement converted 5 into 6, the enantiomerically-pure core of Ethyl Deoxymonate B 7. The ellagitannins, represented by 10, are single atropisomers around the biphenyl linkage. David R. Spring of the University of Cambridge found (Organic Lett. 2008, 10, 2593) that the chiral constraint of the carbohydrate backbone of 9 directed the absolute sense of the oxidative coupling of the mixed cuprate derived from 9, leading to Sanguiin H-5 10 with high diastereomeric control. A key challenge in the synthesis of the solandelactones, exemplified by 14, is the stereocontrolled construction of the unsaturated eight-membered ring lactone. James D. White of Oregon State University found (J. Org. Chem. 2008, 73, 4139) an elegant solution to this problem, by exposure of the cyclic carbonate 11 to the Petasis reagent, to give 12. Subsequent Claisen rearrangement delivered the eight-membered ring lactone, at the same time installing the ring alkene of Solandelactone E 14. AD-mix usually proceeds with only modest enantiocontrol with terminal alkenes. None the less, Ian Paterson, also of the University of Cambridge, observed (Angew. Chem. Int. Ed. 2008, 47, 3016, Angew. Chem. Int. Ed. 2008, 47, 3021) that bis-dihydroxylation of the diene 17 proceeded to give, after acid-mediated cyclization, the bis-spiro ketal core 18 of Spirastrellolide A Methyl Ester 19 with high diastereocontrol.

Substituted Benzenes: The Saikawa/Nakata Synthesis of Kendomycin

Organic Synthesis ◽

10.1093/oso/9780199965724.003.0062 ◽

2013 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Alkyl Iodide ◽

Benzene Derivative ◽

State University ◽

One Pot ◽

Aryl Iodide ◽

Peking University ◽

Cu Catalyst ◽

San Diego State University ◽

University Of Massachusetts ◽

Jianbo Wang of Peking University described (Angew. Chem. Int. Ed. 2010, 49, 2028) the Au-promoted bromination of a benzene derivative such as 1 with N-bromosuccinimide. In a one-pot procedure, addition of a Cu catalyst followed by microwave heating delivered the aminated product 2. Jian-Ping Zou of Suzhou University and Wei Zhang of the University of Massachusetts, Boston, observed (Tetrahedron Lett. 2010, 51, 2639) that the phosphonylation of an arene 3 proceeded with substantial ortho selectivity. Yonghong Gu of the University of Science and Technology, Hefei, showed (Tetrahedron Lett. 2010, 51, 192) that an arylpropanoic acid 6 could be ortho hydroxylated with PIFA to give 7. Louis Fensterbank, Max Malacria, and Emmanuel Lacôte of UMPC Paris found (Angew. Chem. Int. Ed. 2010, 49, 2178) that a benzoic acid could be ortho aminated by way of the cyano amide 8. Daniel J. Weix of the University of Rochester developed (J. Am. Chem. Soc. 2010, 132, 920) a protocol for coupling an aryl iodide 10 with an alkyl iodide 11 to give 12. Professor Wang devised (Angew. Chem. Int. Ed. 2010, 49, 1139) a mechanistically intriguing alkyl carbonylation of an iodobenzene 10. This is presumably proceeding by way of the intermediate diazo alkane. Usually, benzonitriles are prepared by cyanation of the halo aromatic. Hideo Togo of Chiba University established (Synlett 2010, 1067) a protocol for the direct electrophilic cyanation of an electron-rich aromatic 15. Thomas E. Cole of San Diego State University observed (Tetrahedron Lett. 2010, 51, 3033) that an alkyl dimethyl borane, readily prepared by hydroboration of the alkene with BCl3 and Et3 SiH, reacted with benzoquinone 17 to give 18. Presumably this transformation could also be applied to substituted benzoquinones. When a highly substituted benzene derivative is needed, it is sometimes more economical to construct the aromatic ring. Joseph P. A. Harrity of the University of Sheffield and Gerhard Hilt of Philipps-Universität Marburg showed (J. Org. Chem. 2010, 75, 3893) that the Co-catalyzed Diels-Alder cyloaddition of alkynyl borinate 21 with a diene 20 proceeded with high regiocontrol, to give, after oxidation, the aryl borinate 22.