Functional Group Transformation: The Castle Synthesis of Celogentin C

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Allylic Alcohol ◽  
Efficient Reduction ◽  
Simple Protocol ◽  
Peking University ◽  
Celogentin C ◽  
Purdue University ◽  
Institute Of Technology ◽  
Tertiary Amides ◽  
The University ◽  
Functional Group Transformation

Mark Cushman of Purdue University found (J. Org. Chem. 2010, 75, 3507) that a benzylic methyl ether 1 could be converted to the aldehyde 2 by N -bromosuccinimide. Two equivalents of NBS gave the methyl ester. Ning Jiao of Peking University used (Organic Lett. 2010, 12, 2888) NaN3 followed by DDQ to oxidize a benzylic halide 3 to the nitrile 4. Hugues Miel of Almac Sciences oxidized (Tetrahedron Lett. 2010, 51, 3216) the ketone 5 to the nitro derivative 6. The oxidative conversion of the nitro compound 7 to the ketone 8 described (Tetrahedron Lett. 2009, 50, 6389) by Vera L. Patrocinio Pereira of the Universidade Federal do Rio de Janeiro proceeded without epimerization. Sundarababu Baskaran of the Indian Institute of Technology Madras established (Angew. Chem. Int. Ed. 2010, 49, 804) that oxidative cleavage of the benzylidene acetal 9 delivered 10 with high regioselectivity. The intramolecular alkene dihydroxylation of 11 originated (Angew. Chem. Int. Ed. 2010, 49, 4491) by Erik J. Alexanian of the University of North Carolina gave 12 with high diastereocontrol. Ruimao Hua of Tsinghua University took advantage (J. Org. Chem. 2010, 75, 2966) of the H-donor properties of DMF to develop an efficient reduction of the alkyne 13 to the alkyne 14 . Alejandro F. Barrero of the University of Granada developed (J. Am. Chem. Soc. 2010, 132, 254) Ti (III) conditions for the reduction of the allylic alcohol 15 to the terminal alkene 16. Isolated alkenes were stable to these conditions. P. Veeraraghavan Ramachandran, also of Purdue University, effected (Tetrahedron Lett. 2010, 51, 3167) reductive amination of 17 to 18 using the now readily available NH3 - BH3 . Bin Ma and Wen-Cherng Lee of BiogenIdec developed (Tetrahedron Lett. 2010, 51, 385) a simple protocol for the conversion of an acid 19 to the free amine 20. Marc Lemaire of Université Lyons 1 established (Tetrahedron Lett. 2010, 51, 2092) that the silane 22 reduced primary, secondary, and tertiary amides to the aldehydes.

Stereocontrolled C-O Ring Construction: The Fuwa/Sasaki Synthesis of Attenol A

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Gold Catalysis ◽  
Membered Ring ◽  
Allylic Alcohol ◽  
State University ◽  
Prins Cyclization ◽  
University Of Florida ◽  
University Of Pittsburgh ◽  
Colorado State University ◽  
Institute Of Technology ◽  
The University

Since five-membered ring ethers often do not show good selectivity on equilibration, single diastereomers are best formed under kinetic control. Aaron Aponick of the University of Florida demonstrated (Organic Lett. 2008, 10, 669) that under gold catalysis, the allylic alcohol 1 cyclized to 2 with remarkable diastereocontrol. Six-membered rings also formed with high cis stereocontrol. Ian Cumpstey of Stockholm University showed (Chem. Commun. 2008, 1246) that with protic acid, allylic acetates such as 3 cyclized with clean inversion at the allylic center, and concomitant debenzylation. J. Stephen Clark of the University of Glasgow found (J. Org. Chem. 2008, 73, 1040) that Rh catalyzed cyclization of 5 proceeded with high selectivity for insertion into Ha, leading to the alcohol 6. Saumen Hajra of the Indian Institute of Technology, Kharagpur took advantage (J. Org. Chem. 2008, 73, 3935) of the reactivity of the aldehyde of 7, effecting selective addition of 7 to 8, to deliver, after reduction, the lactone 9. Tomislav Rovis of Colorado State University observed (J. Org. Chem. 2008, 73, 612) that 10 could be cyclized selectively to either 11 or 12. Nadège Lubin-Germain, Jacques Uziel and Jacques Augé of the University of Cergy- Pontoise devised (Organic Lett. 2008, 10, 725) conditions for the indium-mediated coupling of glycosyl fluorides such as 13 with iodoalkynes such as 14 to give the axial C-glycoside 15. Katsukiyo Miura and Akira Hosomi of the University of Tsukuba employed (Chemistry Lett. 2008, 37, 270) Pt catalysis to effect in situ equilibration of the alkene 16 to the more stable regioisomer. Subsequent condensation with the aldehyde 17 led via Prins cyclization to the ether 18. Paul E. Floreancig of the University of Pittsburgh showed (Angew. Chem. Int. Ed. 2008, 47, 4184) that Prins cyclization could be also be initiated by oxidation of the benzyl ether 19 to the corresponding carbocation. Chan-Mo Yu of Sungkyunkwan University developed (Organic Lett. 2008, 10, 265) a stereocontrolled route to seven-membered ring ethers, by Pd-mediated stannylation of allenes such as 21, followed by condensation with an aldehyde.

Functional Group Transformations

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 ◽  
The University

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.

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

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.

Arrays of Stereogenic Centers: The Shin/Chandrasekhar Synthesis of (+)-Lactacystin

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Major Product ◽  
South Florida ◽  
Allylic Alcohol ◽  
Israel Institute ◽  
University Of Illinois ◽  
Enantiomerically Pure ◽  
Boston College ◽  
Stereogenic Centers ◽  
Institute Of Technology ◽  
The University

Kami L. Hull of the University of Illinois established (J. Am. Chem. Soc. 2014, 136, 11256) conditions for the diastereoselective hydroamination of 1 with 2 to give 3. Jon C. Antilla of the University of South Florida employed (Org. Lett. 2014, 16, 5548) an enantiomerically-pure Li phosphate to direct the opening of the prochiral epoxide 4 to 5. Jordi Bujons and Pere Clapés of IQAC-CSIC engineered (Chem. Eur. J. 2014, 20, 12572) an enzyme that mediated the enantioselective addition of glycolaldehyde 7 to an aldehyde 6, leading to 8. Takahiro Nishimura of Kyoto University set (J. Am. Chem. Soc. 2014, 136, 9284) the two stereogenic centers of 11 by adding 10 to the diene 9. Amir H. Hoveyda of Boston College added (J. Am. Chem. Soc. 2014, 136, 11304) the propargylic anion derived from 13 to the aldehyde 12 to give, after oxida­tion, the diol 14. Yujiro Hayashi of Tohoku University constructed (Adv. Synth. Catal. 2014, 356, 3106) 17 by the combination of 15 with 16. Yitzhak Apeloig and Ilan Marek of Technion-Israel Institute of Technology prepared (J. Org. Chem. 2014, 79, 12122) the bromo diol 20 by rearranging the adduct between the alkyne 19 and the acyl silane 18. James P. Morken, also of Boston College, effected (J. Am. Chem. Soc. 2014, 136, 17918) enantioselective coupling of 22 with the bis-borane 21. The prod­uct allyl borane added to benzaldehyde to give the alcohol 23. Sentaro Okamoto of Kanagawa University reduced (Org. Lett. 2014, 16, 6278) the aryl oxetane 24 to an intermediate that coupled with allyl bromide to give the alco­hol 25. In the presence of catalytic CuCN, the alternative diastereomer was the major product. Erick M. Carreira of ETH Zürich used (Angew. Chem. Int. Ed. 2014, 53, 13898) a combination of an Ir catalyst and an organocatalyst to couple the aldehyde 27 with the allylic alcohol 26. The four possible combinations of enantiomerically pure catalysts worked equally well, enabling the preparation of each of the four enan­tiomerically pure diastereomers of 28.

Enantioselective Preparation of Alcohols and Amines: The Lam Synthesis of (+)-Tanikolide

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Amino Acids ◽  
Conjugate Addition ◽  
Allylic Alcohol ◽  
University Of Virginia ◽  
Chiral Amine ◽  
Aliphatic Aldehydes ◽  
Nucleophilic Rearrangement ◽  
Silyl Acetals ◽  
Institute Of Technology ◽  
The University

Takashi Ooi of Nagoya University effected (J. Am. Chem. Soc. 2010, 132, 12240) the enantioselective protonation of ketene silyl acetals such as 1 to give 2 in high ee. Hyeon-Kyu Lee of the Korean Research Institute of Chemical Technology achieved (Org. Lett. 2010, 12, 4184) high ee in the hydrogenation of the cyclic sulfamidate 3 to 4. Doo Ok Jang of Yonsei University combined (J. Am. Chem. Soc. 2010, 132, 12168) the nucleophilic allyl indium with a protonated chiral amine to effect homologation of 5 to 6. Ryo Shintani and Tamio Hayashi of Kyoto University reported (Org. Lett. 2010, 12, 4106) a related advance with tetraarylborates. Kazuaki Ishihara, also of Nagoya University (Org. Lett. 2010, 12, 3502) and Yoshihiro Sohtome and Kazuo Nagasawa of the Tokyo University of Agriculture and Technology (Angew. Chem. Int. Ed. 2010, 49, 9254) devised conditions for adding malonate to imines such as 7. Professors Shintani and Hayashi also employed (J. Am. Chem. Soc. 2010, 132, 13168) tetraarylborates to convert 9 to the α-quaternary amine 10. Professor Ooi (Angew. Chem. Int. Ed. 2010, 49, 5567) and Wanbin Zhang of Shanghai Jiao Tong University (J. Am. Chem. Soc. 2010, 132, 15939) prepared α-quaternary amino acids such as 12 by nucleophilic rearrangement of 11. Keiji Maruoka, also of Kyoto University, reported (J. Am. Chem. Soc. 2010, 132, 17074; not illustrated) a catalytic enantioselective conjugate addition approach to α-quaternary amines. Shuji Akai of the University of Shizuoka converted (Org. Lett. 2010, 12, 4900) the racemic allylic alcohol 13 to the enantiomerically enriched acetate 14 by combining V-catalyzed equilibration with lipase-catalyzed acylation. Toshiro Harada of the Kyoto Institute of Technology added (Org. Lett. 2010, 12, 5270) the alkenylboron 16 to the aldehyde 15 with high ee. Xiang Zhou of Wuhan University and Lin Pu of the University of Virginia significantly improved (Tetrahedron Lett . 2010, 51, 5024) a protocol for the enantioselective addition of aliphatic alkynes to aliphatic aldehydes. For other enantioselective additions to aldehydes (not illustrated), see J. Org. Chem. 2010, 75 , 5326 and Org. Lett. 2010, 12, 5088.

C-C Single Bond Construction

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Aryl Halide ◽  
Allylic Alcohol ◽  
University Of Alabama ◽  
Max Planck ◽  
One Pot ◽  
Single Diastereomer ◽  
Institute Of Technology ◽  
The University ◽  
École Polytechnique

Several remarkable one-carbon homologations have recently appeared. André B. Charette of the Université de Montréal reported (J. Org. Chem. 2008, 73, 8097) the alkylation of diiodomethane with alkyl iodides such as 1, to give the diiodoalkane 2. Carlo Punta and the late Ombretta Porta of the Politecnico di Milano effected (Organic Lett. 2008, 10, 5063) reductive condensation of an amine 3 with an aldehyde 4 in the presence of methanol, to give the amino alcohol 5. Timothy S. Snowden of the University of Alabama showed (Organic Lett. 2008, 10, 3853) that NaBH4 reduced the carbinol 7, easily prepared from the aldehyde 6, to the acid 8. Ram N. Ram of the Indian Institute of Technology, Delhi found (J. Org. Chem. 2008, 73, 5633) that CuCl reduced 7 to the chloro ketone 9. Kálmán J. Szabó of Stockholm University extended (Chem. Commun. 2008, 3420) his elegant work on in situ borinate formation, coupling, in one pot, the allylic alcohol 10 with the acetal 11 (hydrolysed in situ) to deliver the alcohol 12 as a single diastereomer. Samir Z. Zard of the Ecole Polytechnique developed (J. Am. Chem. Soc. 2008, 130, 8898) the 6-fluoropyridyloxy ether of 13 as an effective radical leaving group, enabling efficient coupling with 14, activated by dilauroyl peroxide, to give 15. Shu Kobayashi of the University of Tokyo established (Chem. Commun. 2008, 6354) that the anion of the sulfonyl imidate 17 participated in direct Pd-mediated allylic coupling with the carbonate 16. The product sulfonyl imidate 18 is itself of medicinal interest. It is also easily converted to other functional groups, including the aldehyde 19. Jianliang Xiao of the University of Liverpool found (J. Am. Chem. Soc. 2008, 130, 10510) that Pd-mediated coupling of an aldehyde 21 in the presence of pyrrolidine led to the ketone 22. The reaction is probably proceeding via Heck coupling of the aryl halide with the in situ generated enamine. Alois Fürstner of the Max Planck Institut, Mülheim observed (J. Am. Chem. Soc. 2008, 130, 8773) that in the presence of the simple catalyst Fe(acac)3 a Grignard reagent 24 coupled smoothly with an aryl halide 23 to give 25.

C–O Ring Construction: The Tong Synthesis of (−)-Aculeatin A

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
University Of Pittsburgh ◽  
Enantiomerically Pure ◽  
Complementary Approach ◽  
Single Diastereomer ◽  
Pure Alcohol ◽  
Peking University ◽  
Duke University ◽  
Purdue University ◽  
Leaving Groups ◽  
The University

Oxetanes are both interesting structural elements and activated leaving groups. James A. Bull of Imperial College London cyclized (Chem. Commun. 2014, 50, 5203) the tosylate 1 to the oxetane with LiHMDS, then alkylated the product using the same base to give 2. J. S. Yadav of CSIR-Indian Institute of Chemical Technology estab­lished (Org. Lett. 2014, 16, 836) conditions for the cyclization of 3 to 4. Hiroaki Sasai of Osaka University used (Chem. Commun. 2013, 49, 11224) a Pd(II)–Pd(IV) cycle to convert 5 to 6. Lauri Vares of the University of Tartu dem­onstrated (Tetrahedron Lett. 2014, 55, 3569) that the racemic epoxide 7, a mixture of diastereomers, could be cyclized to 8 as a single diastereomer in high ee. Alistair Boyer of the University of Glasgow converted (Org. Lett. 2014, 16, 1660) the tria­zole 9, prepared from the corresponding alkyne, to the intermediate 10, that could be hydrolyzed to the ketone or reduced to the amine. Subhas Chandra Roy of the Indian Association for the Cultivation of Science devised (Eur. J. Org. Chem. 2014, 2980) a Ti(III)- mediated cascade conjugate addition–cyclization for the assembly of 12 from 11. Paul E. Floreancig of the University of Pittsburgh reported (Angew. Chem. Int. Ed. 2014, 53, 4926) the highly diastereoselective reductive cyclization of 13 to 14. Arun K. Ghosh of Purdue University prepared (J. Org. Chem. 2014, 79, 5697) the ketone 16 from the enantiomerically-pure alcohol 15. Professor Ghosh also described (Org. Lett. 2014, 16, 3154) a complementary approach to tetrahydropyrans based on the hetero Diels–Alder addition of the alkynyl aldehyde 18 to the diene 17 to give 19. Xin-Shan Ye of Peking University found (J. Org. Chem. 2014, 79, 4676) that the alcohol 20 could be cyclized to 21 with NBS, and to the diastereomer with PhSeCl. Jiyong Hong of Duke University showed (Org. Lett. 2014, 16, 2406) that an organo­catalyst could be used to mediate the cyclization of 22 to the oxepane 23. Mingji Dai, also of Purdue University, reported (Angew. Chem. Int. Ed. 2014, 53, 6519) the car­bonylative macrocyclization of the diol 24 to the lactone 25.

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

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Secondary Alcohol ◽  
Allylic Alcohol ◽  
Princeton University ◽  
Terminal Alkene ◽  
National University ◽  
Amino Amide ◽  
Enantioselective Epoxidation ◽  
Enantioselective Addition ◽  
Institute Of Technology ◽  
The University

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.

Stereocontrolled C-N Ring Construction: The Takayama Synthesis of Lycoposerramine-C

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Biological Activity ◽  
Total Synthesis ◽  
Gold Catalyst ◽  
Allylic Alcohol ◽  
Tetramic Acids ◽  
Tokyo Institute ◽  
Chiral Bronsted Acid ◽  
Institute Of Technology ◽  
The University ◽  
Technological University

Hideki Yorimitsu and Koichiro Ochima of Kyoto University extended (Angew. Chem. Int. Ed. 2009, 48, 7224) Pd-catalyzed intramolecular carboamidation to the construction of aziridines such as 3. Hamdullah Kilic of Ataturk University showed (J. Org. Chem. 2009, 74, 9452) that aziridination of an allylic alcohol 4 could proceed with substantial diastereocontrol. Makoto Oba of Tokai University established (Tetrahedron Lett. 2009, 50, 5053) a route from a serine derivative 6 to the pyroglutamate 8 and developed a protocol for the conversion of 8 to 9. David Tanner of the Technical University of Denmark found (J. Org. Chem. 2009, 74, 5032) that tetramic acids such as 8 could also be efficiently α-arylated. Koichi Mikami of the Tokyo Institute of Technology devised (Angew. Chem. Int. Ed. 2009, 48, 6073) a gold catalyst for the enantioselective cyclization of 12 to 13. Hiroaki Sasai of Osaka University effected (J. Org. Chem. 2009, 74, 9274) double intramolecular amination, converting 14 into 15 in high ee. Kyungsoo Oh of IUPUI Indianapolis observed (Angew. Chem. Int. Ed. 2009, 48, 7420) that using the same ligand, Cu catalysis gave one enantiomer of 18 and Ag catalysis gave the opposite enantiomer. Liu-Zhu Gong of the University of Science and Technology, Hefei, devised (Organic Lett. 2009, 11, 4946) a chiral Brønsted acid that mediated the enantioselective condensation of 19, 20, and 21 to give 22. Roderick W. Bates of Nanyang Technological University found (Organic Lett. 2009, 11, 3706) that a gold catalyst mediated the cyclization of 23 to 24 with high diastereocontrol. Qi-Lin Zhou of Nankai University effected (Organic Lett. 2009, 11, 4994) the enantioselective reduction of racemic 25 under epimerizing conditions, leading to 26 with high stereocontrol. Adriaan J. Minnaard and Ben L. Feringa of the University of Groningen established (Angew. Chem. Int. Ed. 2009, 48, 9339) conditions for the enantioselective addition of a diakyl zinc to the activated pyridine 27, to give 28 in high ee. Hiromitsu Takayama of Chiba University isolated (Tetrahedron Lett. 2002, 43, 8307) lycoposerramine- C 34 from Lycopodium serratum. Intrigued by preliminary studies of the biological activity but lacking material, he developed (Organic Lett. 2009, 11, 5554) a total synthesis, the key step of which was the intramolecular Pauson-Khand cyclization of 32 to 33.

Metal-Mediated Carbocyclic Construction: The Whitby Synthesis of (+)-Mucosin

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Fischer Carbene ◽  
Heck Cyclization ◽  
Peking University ◽  
Rh Catalyst ◽  
Tokyo Institute ◽  
Hydride Elimination ◽  
Institute Of Technology ◽  
The University

Erick M. Carreira of ETH-Zürich generated (Org. Lett. 2012, 14, 2162) ethyl diazoacetate in situ in the presence of the alkene 1 and an iron catalyst to give the cyclopropane 3. Joseph M. Fox of the University of Delaware inserted (Chem. Sci. 2012, 3, 1589) the Rh carbene derived from 5 into the alkene 4 to give the cyclopropene 6, without β-hydride elimination. Masaatsu Adachi and Toshio Nishikawa of Nagoya University reduced (Chem. Lett. 2012, 41, 287) the enone 7 to give the cyclobutanol 8. Intramolecular ketene cycloaddition has been limited to very electron-rich acceptor alkenes. Xiao-Ping Cao and Yong-Qiang Tu of Lanzhou University devised (Chem. Sci. 2012, 3, 1975) a protocol that converted 9 into the cyclobutanone 10 with high diastereocontrol. The intermediate is the tosylhydrazone of the ketone, so a reductive workup would lead to the corresponding cycloalkane. Koichi Mikami of the Tokyo Institute of Technology added (J. Am. Chem. Soc. 2012, 134, 10329) alkyl cuprates to the prochiral enone 11 to give the enolate trapping product 13 in high ee and with high diastereocontrol. Marcus A. Tius of the University of Hawaii found (Angew. Chem. Int. Ed. 2012, 51, 5727) a Pd catalyst for the Nazarov cyclization of 14 to 15. Antoni Riera and Xavier Verdaguer of the Universitat de Barcelona prepared (Org. Lett. 2012, 14, 3534) 16 by enantioselective Pauson-Khand addition to tetramethyl norbornadiene. Conjugate addition followed by retro Diels-Alder could potentially lead to the cyclopentenone 17. The intermolecular Pauson-Khand cyclization often gives mixtures of regioisomers. José Barluenga of the Universidad de Oviedo demonstrated (Angew. Chem. Int. Ed. 2012, 51, 183) an alternative, the addition of an alkenyl lithium 19 to the Fischer carbene 18 leading to 20. Jian-Hua Xie and Qi-Lin Zhou of Nankai University hydrogenated (Adv. Synth. Catal. 2012, 354, 1105; see also Org. Lett. 2012, 14, 2714) the ketone 21 under epimerizing conditions to give the alcohol 22. Kozo Shishido of the University of Tokushima observed (Tetrahedron Lett. 2012, 53, 145) that the intramolecular Heck cyclization of 23 proceeded with high diastereocontrol. Zhi-Xiang Yu of Peking University devised (Org. Lett. 2012, 14, 692) an Rh catalyst for the cyclocarbonylation of 25 to 26.

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