Enantioselective Construction of Alkylated Centers: The Shishido Synthesis of (+)-Helianane

Institute Of Technology ◽

Enantioselective Alkylation ◽

Teck-Peng Loh of Nanyang Technological University developed (Org. Lett. 2011, 13, 876) a catalyst for the enantioselective addition of an aldehyde to the versatile acceptor 2 to give 3. Kirsten Zeitler of the Universität Regensburg employed (Angew. Chem. Int. Ed. 2011, 50, 951) a complementary strategy for the enantioselective coupling of 4 with 5. Clark R. Landis of the University of Wisconsin devised (Org. Lett. 2011, 13, 164) an Rh catalyst for the enantioselective formylation of the diene 7. Don M. Coltart of Duke University alkylated (J. Am. Chem. Soc. 2011, 133, 8714) the chiral hydrazone of acetone to give 9, then alkylated again to give, after hydrolysis, the ketone 11 in high ee. Youming Wang and Zhenghong Zhou of Nankai University effected (J. Org. Chem. 2011, 76, 3872) the enantioselective addition of acetone to the nitroalkene 12. Takeshi Ohkuma of Hokkaido University achieved (Angew. Chem. Int. Ed. 2011, 50, 5541) high ee in the Ru-catalyzed hydrocyanation of 15. Gregory C. Fu, now at the California Institute of Technology, coupled (J. Am. Chem. Soc. 2011, 133, 8154) the 9-BBN borane 18 with the racemic chloride 17 to give 19 in high ee. Scott McN. Sieburth of Temple University optimized (Org. Lett. 2011, 13, 1787) an Rh catalyst for the enantioselective intramolecular hydrosilylation of 20 to 21. Several general methods have been devised for the enantioselective assembly of quaternary alkylated centers. Sung Ho Kang of KAIST Daejon developed (J. Am. Chem. Soc. 2011, 133, 1772) a Cu catalyst for the enantioselective acylation of the prochiral diol 22. Hyeung-geun Park of Seoul National University established (J. Am. Chem. Soc. 2011, 133, 4924) a phase transfer catalyst for the enantioselective alkylation of 24. Peter R. Schreiner of Justus-Liebig University Giessen found (J. Am. Chem. Soc. 2011, 133, 7624) a silicon catalyst that efficiently rearranged the Shi-derived epoxide of 26 to the aldehyde 27. Amir H. Hoveyda of Boston College coupled (J. Am. Chem. Soc. 2011, 133, 4778) 28 with the alkynyl Al reagent 29 to give 30 in high ee. Kozo Shishido of the University of Tokushima prepared (Synlett 2011, 1171) 31 by the Mitsunobu coupling of m-cresol with the enantiomerically pure allylic alcohol.

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 ◽

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.

Construction of Alkylated Stereogenic Centers

Organic Synthesis ◽

10.1093/oso/9780199965724.003.0041 ◽

2013 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Phase Transfer ◽

Conjugate Addition ◽

Enantioselective Hydrogenation ◽

Boronic Acids ◽

National University ◽

Cu Catalyst ◽

Institute Of Technology ◽

Enantioselective Alkylation ◽

Andreas Pfaltz of the University of Basel and Keisuke Suzuki of the Tokyo Institute of Technology showed (Angew. Chem. Int. Ed. 2010, 49, 881) that the iodohydrin of 1 did not interfere with the enantioselective hydrogenation. J. R. Falck of UT Southwestern developed (J. Am. Chem. Soc. 2010, 132, 2424) a procedure for coupling arene boronic acids with a cyano triflate 3, readily available in high ee from the corresponding aldehyde. Anita R. Maguire of University College Cork devised (J. Am. Chem. Soc. 2010, 132, 1184) a Cu catalyst for the enantioselective C-H insertion cyclization of 5 to 6. Jin-Quan Yu of Scripps/La Jolla established (J. Am. Chem. Soc. 2010, 132, 460) a complementary enantioselective C-H functionalization protocol, converting the prochiral 7 into 8 in high ee. Xumu Zhang of Rutgers University effected (Angew. Chem. Int. Ed. 2010, 49, 4047) enantioselective branching hydroformylation of 9 to give 10. T. V. RajanBabu of Ohio State University established (J. Am. Chem. Soc. 2010, 132, 3295) the enantioselective hydrovinylation of a diene 11 to the diene 12. Gregory C. Fu extended (J. Am. Chem. Soc. 2010, 132, 1264, 5010) Ni-mediated cross-coupling, both with alkenyl and aryl nucleophiles, to the racemic bromoketone 13. Hyeung-geun Park and Sang-sup Jew of Seoul National University used (Organic Lett. 2010, 12 , 2826) their asymmetric phase transfer protocol to effect the enantioselective alkylation of the amide 15. Kyung Woon Jung of the University of Southern California showed (J. Org. Chem. 2010, 75, 95) that the oxidative Pd-mediated Heck coupling of arene boronic acids to 17 could be effected in high ee. Nicolai Cramer of ETH Zurich observed (J. Am. Chem. Soc. 2010, 132, 5340) high enantioinduction in the cleavage of the prochiral cyclobutanol 19. Alexandre Alexakis of the University of Geneva achieved (Organic Lett. 2010, 12, 1988) the long-sought goal of efficient enantioselective conjugate addition of a Grignard reagent to an unsaturated aldehyde 21. Professor Alexakis also established (Organic Lett. 2010, 12, 2770) conditions for enantioselective conjugate addition to a nitrodiene 23. This procedure worked equally well for β-alkynyl nitroalkenes.

Enantioselective Synthesis of Alcohols and Amines: The Zhu Synthesis of (+)-Trigonoliimine A

Organic Synthesis ◽

10.1093/oso/9780190646165.003.0032 ◽

2017 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Secondary Alcohol ◽

Allylic Alcohol ◽

Princeton University ◽

Terminal Alkene ◽

National University ◽

Amino Amide ◽

Enantioselective Epoxidation ◽

Institute Of Technology ◽

The enantioselective epoxidation of a terminal alkene 1 has been a long-sought goal of organic synthesis. Albrecht Berkessel of the University of Cologne devised (Angew. Chem. Int. Ed. 2013, 52, 8467) a Ti catalyst that mediated the conversion of 1 to 2. Zhi Li of the National University of Singapore described (Chem. Commun. 2013, 49, 11572) a cell-based system that effected the enantioselective epoxidation of 3 to 4. Antonio Mezzetti of ETH Zürich and Francesco Santoro of Firmenich SA carried out (Angew. Chem. Int. Ed. 2013, 52, 10352) the enantioselective hydrogenation of 5 to the allylic alcohol 6. Elena Fernández of the Universitat Rovira i Virgilli and Andrew Whiting of Durham University devised (Org. Lett. 2013, 15, 4810) a protocol for the enantioselective conjugate borylation of the imine derived from 7, leading to the secondary alcohol 8. Benjamin List of the Max-Planck-Institute für Kohlenforschung, Mülheim and Choong Eui Song of Sungkyunkwan University condensed (Angew. Chem. Int. Ed. 2013, 52, 12143) the thioester 10 with the aldehyde 9 to give the alcohol 11. Toshiro Harada of the Kyoto Institute of Technology developed (Org. Lett. 2013, 15, 4198) a general procedure for the enantioselective addition of a terminal alkene 12 to an aldehyde 9. As illustrated by the preparation of 13, this appears to be tolerant of a variety of organic functional groups. Professor Harada also established (Chem. Eur. J. 2013, 19, 17707) a protocol for the enantioselective addition of an alkyne 14 to an aldehyde to give the branched product 15. Chun-Jiang Wang and Xumu Zhang of Wuhan University hydrogenated (Angew. Chem. Int. Ed. 2013, 52, 8416) the alkyne 16 to the protected allylic amine 17. Keiji Maruoka of Kyoto University effected (J. Am. Chem. Soc. 2013, 135, 18036) the enantioselective α-amination of an aldehyde 18, to give 19. David W. C. MacMillan of Princeton University described (J. Am. Chem. Soc. 2013, 135, 11521) a complementary approach, not illustrated. David J. Fox of the University of Warwick reduced (Chem. Commun. 2013, 49, 10022) the ketone 20, then rearranged the resulting secondary alcohol to the α-amino amide 21.

Enantioselective Synthesis of Alkylated Centers: The Fukuyama Synthesis of (–)-Histrionicotoxin

Organic Synthesis ◽

10.1093/oso/9780190200794.003.0039 ◽

2015 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Indian Institute ◽

Enantioselective Synthesis ◽

Max Planck ◽

Dimethyl Malonate ◽

Co Catalyst ◽

Cu Catalyst ◽

Institute Of Technology ◽

Enantioselective Alkylation ◽

Technological University

Vinod K. Singh of the Indian Institute of Technology, Kanpur optimized (Org. Lett. 2011, 13, 6520) an organocatalyst for the enantioselective addition of thiophenol to an imide 1 to give 2 in high ee. Amir H. Hoveyda of Boston College developed (Angew. Chem. Int. Ed. 2011, 50, 7079) a Cu catalyst for the preparation of 4 by the enantioselective hydroboration of a 1,1-disubstituted alkene 3. Yong-Qiang Tu of Lanzhou University effected (Chem. Sci. 2011, 2, 1839) enantioselective bromination of the prochiral 5 to give the bromoketone 6. Song Ye of the Institute of Chemistry, Beijing established (Chem. Commun. 2011, 47, 8388) the alkylated quaternary center of the dimer 8, by condensing a ketene 7 with CS2. Li Deng of Brandeis University added (Angew. Chem. Int. Ed. 2011, 50, 10565) cyanide in a conjugate sense to an acyl imidazole 9 to give 11. Pier Giorgio Cozzi of the Università di Bologna prepared (Angew. Chem. Int. Ed. 2011, 50, 7842) the thioacetal 14 by condensing 13 with an aldehyde 12, followed by reduction. Takahiro Nishimura and Tamio Hayashi of Kyoto University devised (Chem. Commun. 2011, 47, 10142) a Co catalyst for the enantioselective addition of a silyl alkyne 16 to an enone 15 to give the alkynyl ketone 17. Ping Tian and Guo-Qiang Lin of the Shanghai Institute of Organic Chemistry described (Tetrahedron 2011, 67, 10186) improved catalysts for the enantioselective conjugate addition of dimethyl malonate 19 to the nitroalkene 18, to give 20. Keiji Maruoka, also of Kyoto University, established (Chem. Sci. 2011, 2, 2311) conditions for the enantioselective addition of an aldehyde 21 to the acceptor 22 to give, after reduction, an alcohol 23 that could readily be cyclized to the lactone. Jianrong (Steve) Zhou of Nanyang Technological University prepared (J. Am. Chem. Soc. 2011, 133, 15882) the ester 26 by arylation, under Pd catalysis, of a ketene silyl acetal 24 with the triflate 25. Benjamin List of the Max-Planck-Institut, Mülheim employed (Angew. Chem. Int. Ed. 2011, 50, 9471) a system of three catalysts to effect the enantioselective alkylation of an aldehyde 27 with the allyic alcohol 28 to give 29.

Functional Group Transformations

Organic Synthesis ◽

10.1093/oso/9780190200794.003.0003 ◽

2015 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Gold Catalyst ◽

Sulfonyl Chloride ◽

Allylic Alcohol ◽

West Virginia University ◽

Israel Institute ◽

University Of Texas ◽

Amino Amide ◽

Cu Catalyst ◽

Institute Of Technology ◽

Mark Gandelman of the Technion–Israel Institute of Technology devised (Adv. Synth. Catal. 2011, 353, 1438) a protocol for the decarboxylative conversion of an acid 1 to the iodide 3. Doug E. Frantz of the University of Texas, San Antonio effected (Angew. Chem. Int. Ed. 2011, 50, 6128) conversion of a β-keto ester 4 to the diene 5 by way of the vinyl triflate. Pei Nian Liu of the East China University of Science and Technology and Chak Po Lau of the Hong Kong Polytechnic University (Adv. Synth. Catal. 2011, 353, 275) and Robert G. Bergman and Kenneth N. Raymond of the University of California, Berkeley (J. Am. Chem. Soc. 2011, 133, 11964) described new Ru catalysts for the isomerization of an allylic alcohol 6 to the ketone 7. Xiaodong Shi of West Virginia University optimized (Adv. Synth. Catal. 2011, 353, 2584) a gold catalyst for the rearrangement of a propargylic ester 8 to the enone 9. Xue-Yuan Liu of Lanzhou University used (Adv. Synth. Catal. 2011, 353, 3157) a Cu catalyst to add the chloramine 11 to the alkyne 10 to give 12. Kasi Pitchumani of Madurai Kamaraj University converted (Org. Lett. 2011, 13, 5728) the alkyne 13 into the α-amino amide 15 by reaction with the nitrone 14. Katsuhiko Tomooka of Kyushu University effected (J. Am. Chem. Soc. 2011, 133, 20712) hydrosilylation of the propargylic ether 16 to the alcohol 17. Matthew J. Cook of Queen’s University Belfast (Chem. Commun. 2011, 47, 11104) and Anna M. Costa and Jaume Vilarrasa of the Universitat de Barcelona (Org. Lett. 2011, 13, 4934) improved the conversion of an alkenyl silane 18 to the iodide 19. Vinay Girijavallabhan of Merck/Kenilworth developed (J. Org. Chem. 2011, 76, 6442) a Co catalyst for the Markovnikov addition of sulfide to an alkene 20. Hojat Veisi of Payame Noor University oxidized (Synlett 2011, 2315) the thiol 22 directly to the sulfonyl chloride 23. Nicholas M. Leonard of Abbott Laboratories prepared (J. Org. Chem. 2011, 76, 9169) the chromatography-stable O-Su ester 25 from the corresponding acid 24.

Reactions of Alkenes: The RajanBabu Synthesis of Pseudopterosin G-J Aglycone Dimethyl Ether

Organic Synthesis ◽

10.1093/oso/9780190200794.003.0029 ◽

2015 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Medical Center ◽

Selective Reduction ◽

Oxidative Cleavage ◽

University Of Texas ◽

Furman University ◽

National University ◽

Institute Of Technology ◽

The University ◽

Medical University

Xiangge Zhou of Sichuan University showed (Tetrahedron Lett. 2011, 52, 318) that even the monosubstituted alkene 1 was smoothly converted to the methyl ether 2 by catalytic FeCl3. Brian C. Goess of Furman University protected (J. Org. Chem. 2011, 76, 4132) the more reactive alkene of 3 as the 9-BBN adduct, allowing selective reduction of the less reactive alkene to give, after reoxidation, the monoreduced 4. Nobukazu Taniguchi of the Fukushima Medical University added (Synlett 2011, 1308) Na p-toluenesulfinate oxidatively to 1 to give the sulfone 5. Krishnacharya G. Akamanchi of the Indian Institute of Chemical Technology, Mumbai oxidized (Synlett 2011, 81) 1 directly to the bromo ketone 6. Osmium is used catalytically both to effect dihydroxylation, to prepare 8, and to mediate oxidative cleavage, as in the conversion of 7 to the dialdehyde 9. Ken-ichi Fujita of AIST Tsukuba devised (Tetrahedron Lett. 2011, 52, 3137) magnetically retrievable osmium nanoparticles that can be reused repeatedly for the dihydroxylation. B. Moon Kim of Seoul National University established (Tetrahedron Lett. 2011, 52, 1363) an extraction scheme that allowed the catalytic Os to be reused repeatedly for the oxidative cleavage. Maurizio Taddei of the Università di Siena showed (Synlett 2011, 199) that aqueous formaldehyde could be used in place of Co/H2 (syngas) for the formylation of 1 to 10. Hirohisa Ohmiya and Masaya Sawamura of Hokkaido University prepared (Org. Lett. 2011, 13, 1086) carboxylic acids (not illustrated) from alkenes using CO2. Joseph M. Ready of the University of Texas Southwestern Medical Center selectively arylated (Angew. Chem. Int. Ed. 2011, 50, 2111) the homoallylic alcohol 11 to give 12. Many reactions of alkenes are initiated by hydroboration, then conversion of the resulting alkyl borane. Hiroyuki Kusama of the Tokyo Institute of Technology photolyzed (J. Am. Chem. Soc. 2011, 133, 3716) 14 with 13 to give the ketone 15. William G. Ogilvie of the University of Ottawa added (Synlett 2011, 1113) the 9-BBN adduct from 1 to 16 to give 17. Professors Ohmiya and Sawamura effected (Org. Lett. 2011, 13, 482) a similar conjugate addition, not illustrated, of 9-BBN adducts to α,β-unsaturated acyl imidazoles.

Organic Functional Group Interconversion

Organic Synthesis ◽

10.1093/oso/9780190646165.003.0003 ◽

2017 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Reduced Form ◽

Ni Catalyst ◽

Max Planck ◽

University Of Maryland ◽

Ru Catalyst ◽

Maryland School ◽

National University ◽

Rh Catalyst ◽

Alois Fürstner of the Max-Planck-Institut Mülheim devised (Angew. Chem. Int. Ed. 2013, 52, 14050) a Ru catalyst for the trans- selective hydroboration of an alkyne 1 to 2. Qingbin Liu of Hebei Normal University and Chanjuan Xi of Tsinghua University coupled (Org. Lett. 2013, 15, 5174) the alkenyl zirconocene derived from 3 with an acyl azide to give the amide 4. Chulbom Lee of Seoul National University used (Angew. Chem. Int. Ed. 2013, 52, 10023) a Rh catalyst to convert a terminal alkyne 5 to the ester 6. Laura L. Anderson of the University of Illinois, Chicago devised (Org. Lett. 2013, 15, 4830) a protocol for the conversion of a terminal alkyne 7 to the α-amino aldehyde 9. Dewen Dong of the Changchun Institute of Applied Chemistry developed (J. Org. Chem. 2013, 78, 11956) conditions for the monohydrolysis of a bis nitrile 10 to the monoamide 11. Aiwen Lei of Wuhan University optimized (Chem. Commun. 2013, 49, 7923) a Ni catalyst for the conversion of the alkene 12 to the enamide 13. Kazushi Mashima of Osaka University optimized (Adv. Synth. Catal. 2013, 355, 3391) a boronic ester catalyst for the conversion of an amide 14 to the ester 15. Jean- François Paquin of the Université Laval prepared (Eur. J. Org. Chem. 2013, 4325) the amide 17 by coupling an amine with the activated intermediate from reaction of an acid 16 with Xtal- Fluor E. Steven Fletcher of the University of Maryland School of Pharmacy designed (Tetrahedron Lett. 2013, 54, 4624) the azodicarbonyl dimorpholide 18 as a reagent for the Mitsunobu coupling of 19 with 20. The reduced form of 18 was readily separated by extraction into water and reoxidized. Jens Deutsch of the Universität Rostock found (Chem. Eur. J. 2013, 19, 17702) simple ligands for the Ru-mediated borrowed hydrogen conversion of an alcohol 22 to the amine 23. Ronald T. Raines of the University of Wisconsin devised (J. Am. Chem. Soc. 2013, 135, 14936) a phosphinoester for the efficient conversion in water of an azide 24 to the diazo 25.

Alkene and Alkyne Metathesis: Navenone B (Cossy), (+)-Asperpentyn (Daesung Lee), (-)-Amphidinolide K (Eun Lee), Norhalichondrin B (Phillips)

Organic Synthesis ◽

10.1093/oso/9780199965724.003.0031 ◽

2013 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Allylic Alcohol ◽

Alkyne Metathesis ◽

University Of Illinois ◽

Cross Metathesis ◽

Synthetic Strategy ◽

University Of Colorado ◽

National University ◽

The Cross ◽

A variety of antibiotics and immune-suppressive agents contain extended arrays of all- ( E )-polyenes. Samir Bouzbouz of CNS Rouen and Janine Cossy of ESPCI ParisTech devised ( Synlett 2009, 803) a simple iterative route to polyacetates such as 1 and demonstrated that after cross-metathesis, elimination, in this case to give Navenone B 3, was facile. Both ketones and esters can promote the elimination. Daesung Lee of the University of Illinois at Chicago designed (Organic Lett. 2009, 11 , 571) a clever chain-walking ring-closing ene-yne metathesis, cyclizing 4 to 5. Deprotection led to (+)-asperpentyn 6. This should be a general entry to such polyoxygenated cyclohexenes. For the structures of H2 and G2, see Organic Highlights, September 13, 2004. One of the challenges in the synthesis of (-)-amphidinoloide K 10 is the assembly of the complex conjugated diene. Eun Lee of Seoul National University found (Angew. Chem. Int. Ed. 2009, 48, 2364) a solution to this problem in the Ru-catalyzed cross-metathesis between the alkyne 7 and the alkene 8. Note that the cross-metathesis proceeded with high regioselectivity and with substantial (7.5:1) control of the product alkene geometry. For the construction of complex natural products such as norhalichondrin B 14, it is important to employ a convergent synthetic strategy. For this to be successful, efficient methods for convergent coupling are required. In the course of a synthesis of 14, Andrew J. Phillips of the University of Colorado showed (Angew. Chem. Int. Ed. 2009, 48, 2346) that Ru-mediated cross-metathesis could be used to couple the enone 11 with the alkene 12. A less congested version of H2, designed by Robert H. Grubbs of Caltech, was used for the coupling. The electron-deficient alkene of 11 and the more electron-rich alkene of 12 made a matched set, promoting the cross-coupling. Note again, in this context, the desirability of leaving the allylic alcohol of 12 unprotected to facilitate Ru-catalyzed alkene cross-metathesis.

Metal-Mediated Ring Construction: The Hoveyda Synthesis of (–)-Nakadomarin A

Organic Synthesis ◽

10.1093/oso/9780190200794.003.0077 ◽

2015 ◽

Author(s):

Douglass F. Taber

Keyword(s):

Preliminary Investigation ◽

State University ◽

Colorado State University ◽

Nakadomarin A ◽

Sterically Demanding ◽

National University ◽

Rh Catalyst ◽

The University ◽

Technological University

John F. Hartwig of the University of California, Berkeley effected (J. Am. Chem. Soc. 2013, 135, 3375) selective borylation of the cyclopropane 1 to give 2. It would be particularly useful if this borylation could be made enantioselective. Eric M. Ferreira of Colorado State University showed (Org. Lett. 2013, 15, 1772) that the enantomeric excess of 3 was transferred to the highly substituted cyclopropane 4. Antonio M. Echavarren of ICIQ Tarragona demonstrated (Org. Lett. 2013, 15, 1576) that Au-mediated cyclobutene construction could be used to form the medium ring of 6. Joseph M. Fox of the University of Delaware developed (J. Am. Chem. Soc. 2013, 135, 9283) what promises to be a general enantioselective route to cyclobutanes such as 8 by way of the intermediate bicyclobutane (not illustrated). Huw M.L. Davies of Emory University reported (Org. Lett. 2013, 15, 310) a preliminary investigation in this same direction. Masahisa Nakada of Waseda University prepared (Org. Lett. 2013, 15, 1004) the cyclopentane 10 by enantioselective cyclization of 9 followed by reductive opening. Young-Ger Suh of Seoul National University cyclized (Org. Lett. 2013, 15, 531) the lactone 11 to the cyclopentane 12. Xavier Ariza and Jaume Farràs of the Universitat de Barcelona optimized (J. Org. Chem. 2013, 78, 5482) the Ti-mediated reductive cyclization of 13 to 14. The hydrogenation catalyst reduced the intermediate Ti–C bond without affecting the alkene. Erick M. Carreira of ETH Zürich observed (Angew. Chem. Int. Ed. 2013, 52, 5382) that a sterically demanding Rh catalyst mediated the highly diastereoselective cyclization of 15 to 16. The ketone 16 was the key intermediate in a synthesis of the epoxyisoprostanes. Jianrong (Steve) Zhou of Nanyang Technological University used (Angew. Chem. Int. Ed. 2013, 52, 4906) a Pd catalyst to effect the coupling of 17 with the prochiral 18. Geum-Sook Hwang and Do Hyun Ryu of Sungkyunkwan University devised (J. Am. Chem. Soc. 2013, 135, 7126) a boron catalyst to effect the addition of the diazo ester 21 to 20. They showed that the sidechain stereocenter was effective in directing the subsequent hydrogenation of 22.

Enantioselective Synthesis of Alcohols and Amines: The Doi Synthesis of Apratoxin C

Organic Synthesis ◽

10.1093/oso/9780190646165.003.0034 ◽

2017 ◽

Author(s):

Douglass F. Taber

Keyword(s):

South Florida ◽

Allylic Alcohol ◽

Chemistry Laboratory ◽

University Of Maryland ◽

Ene Reaction ◽

Quaternary Center ◽

Cu Catalyst ◽

Rh Catalyst ◽

The Face ◽

Hiromitsu Takayama of Chiba University used (Org. Lett. 2014, 16, 5000) the Itsuno-Corey protocol to reduce the enone 1 to the allylic alcohol 2. Peiming Gu of Ningxia University developed (Org. Lett. 2014, 16, 5339) a Cu catalyst that cyclized the prochiral 3 to 4 in high ee. Xiaoming Feng of Sichuan University effected (Org. Lett. 2014, 16, 3938) enantioselective Baeyer–Villiger oxidation of the racemic cyclopentanone 5, converting one enantiomer to the δ-lactone 6. The velocity of catalytic osmylation is often limited by slow turnover of the intermediate osmate ester. Koichi Narasaka, then at the University of Tokyo, showed (Chem. Lett. 1988, 1721) that the efficiency of the transformation was improved by the addition of stoichiometric phenyl boronic acid. Kilian Muñiz, now at ICIQ Tarragona, established (Chem. Eur. J. 2005, 11, 3951) that this acceleration also worked with Sharpless asymmetric dihydroxylation. D. Christopher Braddock of Imperial College London took advantage (Chem. Commun. 2014, 50, 13725) of these observations, converting myrcene 7 selectively to the cyclic boronate 8. Michael P. Doyle of the University of Maryland developed (J. Org. Chem. 2014, 79, 12185) a Rh catalyst for the ene reaction of 9 with 10 to give 11. Adriaan J. Minnaard of the University of Groningen devised (Chem. Eur. J. 2014, 20, 14250) a Cu catalyst that mediated the face selective addition of 13 to 12, establishing the oxygenated quaternary center of 14. Tomonori Misaki and Takashi Sugimura of the University of Hyogo used (Chem. Lett. 2014, 43, 1826) Michael addition of 15 to 16 to construct the oxygenated quaternary center of 17. Jon C. Antilla of the University of South Florida assembled (Chem. Commun. 2014, 50, 14187) the δ-lactone 20 by adding the diene 19 to the α-keto ester 18. Zhiyong Wang of the University of Science and Technology of China reported (Org. Lett. 2014, 16, 3564) related results. Jonathan A. Ellman of Yale University achieved (Angew. Chem. Int. Ed. 2014, 53, 11329) substantial enantioselectivity in the addition of thioacetic acid 22 to the nitroalkene 21 to give 23. Subhash P. Chavan of the National Chemistry Laboratory prepared (Tetrahedron Lett. 2014, 55, 5905) the allylic amine 25 by reduction of the aziridine 24.