Organocatalyzed Carbocyclic Construction: (+)-Roseophilin (Flynn) and (+)-Galbulin (Hong)

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Conjugate Addition ◽  
State University ◽  
Max Planck ◽  
University Of Wisconsin ◽  
Georgia State University ◽  
Enantioselective Addition ◽  
The University ◽  
Pais Vasco

Armido Studer of Wilhems-University Münster effected (Chem. Commun. 2012, 48, 5190) the enantioselective conjugate addition of 2 to 1, leading to the cyclopropane 3. Karl Anker Jørgensen of Aarhus University devised (J. Am. Chem. Soc. 2012, 134, 2543) a route to cyclobutanes based on the enantioselective addition of 5 to the nitroalkene 4. Jose L. Vicario of the Universidad del País Vasco reported (Angew. Chem. Int. Ed. 2012, 51, 4104) a similar procedure. Benjamin List of the Max-Planck-Institute Mülheim epoxidized (Adv. Synth. Catal. 2012, 354, 1701) cyclopentenones such as 7 with high ee. Lutz H. Gade of the Universität Heidelberg observed (J. Am. Chem. Soc. 2012, 134, 2946) high ee in the benzylation of 9. Cheng Ma of Zhejiang University formylated (J. Org. Chem. 2012, 77, 2959) cyclopentanone, then condensed the resulting aldehyde 12 with 13 to give 14. Hao Xu of Georgia State University cyclized (Org. Lett. 2012, 14, 858) 15 to the cyclopentenone 16. (+)-Rosephilin 19 inhibits several phosphatases. Bernard L. Flynn of Monash University prepared (Org. Lett. 2012, 14, 1740) the carbocyclic core of 19 by cyclizing 17 to the cyclopentenone 18. Masanori Yoshida of Hokkaido University designed (J. Org. Chem. 2011, 76, 8513) a very simple organocatalyst for the enantioselective conjugate addition of 21 to 20. Samuel H. Gellman of the University of Wisconsin showed (Org. Lett. 2012, 14, 2582) that nitromethane could be added to 23 with high ee. Hiroaki Sasai of Osaka University effected (Angew. Chem. Int. Ed. 2012, 51, 5423) the enantioselective cyclization of the prochiral 25. Ying-Chun Chen of Sichuan University found (Angew. Chem. Int. Ed. 2012, 51, 4401) that the diene 27 could be converted to 29 by way of the intermediate trienamine. Bor-Cherng Hong of the National Chung Cheng University observed (Chem. Commun. 2012, 48, 2385) that under organocatalysis, only one enantiomer of 31 would add to 30, delivering 32 in high ee. Aromatization of 32 led to (+)-galbulin 33.

New Methods for C-C Bond Construction: The Burke Synthesis of (-)-Peridinin

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Ohio State University ◽  
Florida State University ◽  
State University ◽  
University Of Kansas ◽  
University Of Mississippi ◽  
Max Planck ◽  
Enantiomerically Pure ◽  
University Of Wisconsin ◽  
Northwestern University ◽  
The University

Hideki Yorimitsu and Koichiro Oshima of Kyoto University observed (J. Am. Chem. Soc. 2010, 132, 8878) that Rh-catalyzed addition of 2 to a terminal allene 1 generated an allylic organometallic, which coupled with electrophiles to give the branched product 3. Regan J. Thomson of Northwestern University devised (Nat. Chem. 2010, 2, 294) the reagent 5, which added to an aldehyde 4 to give the reduced allylically coupled product 6. Nuno Maulide of the Max-Planck-Institut, Mülheim, noted (Angew. Chem. Int. Ed. 2010, 49, 1583) the remarkable rearrangement of 7 to 8. Jon A. Tunge of the University of Kansas showed (Organic Lett. 2010, 12, 740) that nitronate allylation could be effected by the Pd-mediated decarboxylation of 9. Takashi Tomioka of the University of Mississippi developed (Organic Lett. 2010, 12, 2171) a convenient reagent for the conversion of an aldehyde 11 to the Z -unsaturated nitrile 12 . Xiaodong Shi of the University of West Virginia established (Organic Lett. 2010, 12, 2088) that Au-mediated rearrangement of 13 led to the Z -iodo enone 14. T. V. RajanBabu of Ohio State University developed (Organic Lett. 2010, 12, 2622) a Pd catalyst for the selective double functionalization of a terminal alkyne 15 to the stannane 16. The subsequent tandem Stille and Suzuki couplings proceeded efficiently. The controlled construction of tetrasubstituted alkenes is particularly challenging. Kohei Endo and Takanori Shibata of Waseda University put forward (J. Org. Chem. 2010, 75, 3469) what promises to be a general solution to this problem: the addition of the bis-boronate 17 to a ketone 18. Alkynes are usually prepared by direct alkylation. Gérard Cahiez of the Université de Paris 13 established (Angew. Chem. Int. Ed. 2010, 49, 1278) an alternative: the coupling of a Grignard reagent with a 1-bromoalkyne 20. Gregory B. Dudley of Florida State University developed (J. Org. Chem. 2010, 75, 3260) a complementary route to internal alkynes based on the fragmentation of 22. Enantiomerically pure allenes are ubiquitous components of physiologically active natural products. Weiping Tang of the University of Wisconsin optimized (J. Am. Chem. Soc. 2010, 132, 3664) the bromolactonization of a Z enyne 24 to give the allene 25.

Other Methods for Carbocyclic Construction: The Porco Synthesis of (-)-Hyperibone K

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Oxidative Cyclization ◽  
Florida State University ◽  
State University ◽  
Colorado State University ◽  
Intramolecular Alkylation ◽  
University Of Wisconsin ◽  
Tokyo Institute ◽  
Institute Of Technology ◽  
University Of Bristol ◽  
The University

Varinder K. Aggarwal of the University of Bristol described (Angew. Chem. Int. Ed. 2010, 49, 6673) the conversion of the Sharpless-derived epoxide 1 into the cyclopropane 2. Christopher D. Bray of Queen Mary University of London established (Chem. Commun. 2010, 46, 5867) that the related conversion of 3 to 5 proceeded with high diastereocontrol. Javier Read de Alaniz of the University of California, Santa Barbara, extended (Angew. Chem. Int. Ed. 2010, 49, 9484) the Piancatelli rearrangement of a furyl carbinol 6 to allow inclusion of an amine 7, to give 8. Issa Yavari of Tarbiat Modares University described (Synlett 2010, 2293) the dimerization of 9 with an amine to give 10. Jeremy E. Wulff of the University of Victoria condensed (J. Org. Chem. 2010, 75, 6312) the dienone 11 with the commercial butadiene sulfone 12 to give the highly substituted cyclopentane 13. Robert M. Williams of Colorado State University showed (Tetrahedron Lett. 2010, 51, 6557) that the condensation of 14 with formaldehyde delivered the cyclopentanone 15 with high diastereocontrol. D. Srinivasa Reddy of Advinus Therapeutics devised (Tetrahedron Lett. 2010, 51, 5291) conditions for the tandem conjugate addition/intramolecular alkylation conversion of 16 to 17. Marie E. Krafft of Florida State University reported (Synlett 2010, 2583) a related intramolecular alkylation protocol. Takao Ikariya of the Tokyo Institute of Technology effected (J. Am. Chem. Soc. 2010, 132, 11414) the enantioselective Ru-mediated hydrogenation of bicyclic imides such as 18. This transformation worked equally well for three-, four-, five-, six-, and seven-membered rings. Stefan France of the Georgia Institute of Technology developed (Org. Lett. 2010, 12, 5684) a catalytic protocol for the homo-Nazarov rearrangement of the doubly activated cyclopropane 20 to the cyclohexanone 21. Richard P. Hsung of the University of Wisconsin effected (Org. Lett. 2010, 12, 5768) the highly diastereoselective rearrangement of the triene 22 to the cyclohexadiene 23. Strategies for polycyclic construction are also important. Sylvain Canesi of the Université de Québec devised (Org. Lett. 2010, 12, 4368) the oxidative cyclization of 24 to 25.

Establishing Arrays of Stereogenic Centers: The Sato/Chida Synthesis of (-)-Kainic Acid

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Catalyst System ◽  
Allylic Alcohol ◽  
University Of Pennsylvania ◽  
Ni Catalyst ◽  
Max Planck ◽  
Stereogenic Centers ◽  
University College London ◽  
Enantioselective Addition ◽  
La Jolla ◽  
The University

Benjamin List of the Max-Planck-Institut, Mülheim, devised (J. Am. Chem. Soc. 2010, 132, 10227) a catalyst system for the stereocontrolled epoxidation of a trisubstituted alkenyl aldehyde 1. Takashi Ooi of Nagoya University effected (Angew. Chem. Int. Ed. 2010, 49, 7562; see also Org. Lett. 2010, 12, 4070) enantioselective Henry addition to an alkynyl aldehyde 3. Madeleine M. Joullié of the University of Pennsylvania showed (Org. Lett. 2010, 12, 4244) that an amine 7 added selectively to an alkynyl aziridine 6. Yutaka Ukaji and Katsuhiko Inomata of Kanazawa University developed (Chem. Lett. 2010, 39, 1036) the enantioselective dipolar cycloaddition of 9 with 10. K. C. Nicolaou of Scripps/La Jolla observed (Angew. Chem. Int. Ed. 2010, 49, 5875; see also J. Org. Chem. 2010, 75, 8658) that the allylic alcohol from enantioselective reduction of 12 could be hydrogenated with high diastereocontrol. Masamichi Ogasawara and Tamotsu Takahashi of Hokkaido University added (Org. Lett. 2010, 12, 5736) the allene 14 to the acetal 15 with substantial stereocontrol. Helen C. Hailes of University College London investigated (Chem. Comm. 2010, 46, 7608) the enzyme-mediated addition of 18 to racemic 17. Dawei Ma of the Shanghai Institute of Organic Chemistry, in the course of a synthesis of oseltamivir (Tamiflu), accomplished (Angew. Chem. Int. Ed. 2010, 49, 4656) the enantioselective addition of 21 to 20. Shigeki Matsunaga of the University of Tokyo and Masakatsu Shibasaki of the Institute of Microbial Chemistry developed (Org. Lett. 2010, 12, 3246) a Ni catalyst for the enantioselective addition of 23 to 24. Juthanat Kaeobamrung and Jeffrey W. Bode of ETH-Zurich and Marisa C. Kozlowski of the University of Pennsylvania devised (Proc. Natl. Acad. Sci. 2010, 107, 20661) an organocatalyst for the enantioselective addition of 27 to 26. Yihua Zhang of China Pharmaceutical University and Professor Ma effected (Tetrahedron Lett. 2010, 51, 3827) the related addition of 27 to 29. There have been scattered reports on the stereochemical course of the coupling of cyclic secondary organometallics. In a detailed study, Paul Knochel of Ludwig-Maximilians- Universität München showed (Nat. Chem. 2020, 2, 125) that equatorial bond formation dominated, exemplified by the conversion of 31 to 33.

C–O Natural Products: (–)-Hybridalactone (Fürstner), (+)-Anthecotulide (Hodgson), (–)-Kumausallene (Tang), (±)-Communiol E (Kobayashi), (–)-Exiguolide (Scheidt), Cyanolide A (Rychnovsky)

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Max Planck ◽  
Enantiomerically Pure ◽  
University Of Oxford ◽  
University Of Wisconsin ◽  
Favorskii Rearrangement ◽  
Alternative Approach ◽  
Ether Oxygen ◽  
Institute Of Technology ◽  
The University ◽  
Complementary Strategy

Control of the absolute configuration of adjacent alkylated stereogenic centers is a classic challenge in organic synthesis. In the course of the synthesis of (–)-hybridalactone 4, Alois Fürstner of the Max-Planck-Institut Mülheim effected (J. Am. Chem. Soc. 2011, 133, 13471) catalytic enantioselective conjugate addition to the simple acceptor 1. The initial adduct, formed in 80% ee, could readily be recrystallized to high ee. In an alternative approach to high ee 2,3-dialkyl γ-lactones, David M. Hodgson of the University of Oxford cyclized (Org. Lett. 2011, 13, 5751) the alkyne 5 to an aldehyde, which was condensed with 6 to give 7. Coupling with 8 then delivered (+)-anthecotulide 9. The enantiomerically pure diol 10 is readily available from acetylacetone. Weiping Tang of the University of Wisconsin dissolved (Org. Lett. 2011, 13, 3664) the symmetry of 10 by Pd-mediated cyclocarbonylation. The conversion of the lactone 11 to (–)-kumausallene 12 was enabled by an elegant intramolecular bromoetherification. Shoji Kobayshi of the Osaka Institute of Technology developed (J. Org. Chem. 2011, 76, 7096) a powerful oxy-Favorskii rearrangement that enabled the preparation of both four-and five-membered rings with good diastereocontrol, as exemplified by the conversion of 13 to 14. With the electron-withdrawing ether oxygen adjacent to the ester carbonyl, Dibal reduction of 14 proceeded cleanly to the aldehyde. Addition of ethyl lithium followed by deprotection completed the synthesis of (±)-communiol E. En route to (–)-exiguolide 18, Karl A. Scheidt of Northwestern University showed (Angew. Chem. Int. Ed. 2011, 50, 9112) that 16 could be cyclized efficiently to 17. The cyclization may be assisted by a scaffolding effect from the dioxinone ring. Dimeric macrolides such as cyanolide A 21 are usually prepared by lactonization of the corresponding hydroxy acid. Scott D. Rychnovsky of the University of California Irvine devised (J. Am. Chem. Soc. 2011, 133, 9727) a complementary strategy, the double Sakurai dimerization of the silyl acetal 19 to 20.

Organocatalyzed C–C Ring Construction: The Mihovilovic Synthesis of Piperenol B

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
State University ◽  
Air Oxidation ◽  
Microbial Oxidation ◽  
Max Planck ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Northwestern University ◽  
National University ◽  
The University ◽  
Oregon State University

M. Kevin Brown of Indiana University prepared (J. Am. Chem. Soc. 2015, 137, 3482) the cyclobutane 3 by the organocatalyzed addition of 2 to the alkene 1. Karl Anker Jørgensen of Aarhus University assembled (J. Am. Chem. Soc. 2015, 137, 1685) the complex cyclobutane 7 by the addition of 5 to the acceptor 4, followed by conden­sation with the phosphorane 6. Zhi Li of the National University of Singapore balanced (ACS Catal. 2015, 5, 51) three enzymes to effect enantioselective opening of the epoxide 8 followed by air oxidation to 9. Gang Zhao of the Shanghai Institute of Organic Chemistry and Zhong Li of the East China University of Science and Technology added (Org. Lett. 2015, 17, 688) 10 to 11 to give 12 in high ee. Akkattu T. Biju of the National Chemical Laboratory combined (Chem. Commun. 2015, 51, 9559) 13 with 14 to give the β-lactone 15. Paul Ha-Yeon Cheong of Oregon State University and Karl A. Scheidt of Northwestern University reported (Chem. Commun. 2015, 51, 2690) related results. Dieter Enders of RWTH Aachen University constructed (Chem. Eur. J. 2015, 21, 1004) the complex cyclopentane 20 by the controlled com­bination of 16, 17, and 18, followed by addition of the phosphorane 19. Derek R. Boyd and Paul J. Stevenson of Queen’s University Belfast showed (J. Org. Chem. 2015, 80, 3429) that the product from the microbial oxidation of 21 could be protected as the acetonide 22. Ignacio Carrera of the Universidad de la República described (Org. Lett. 2015, 17, 684) the related oxidation of benzyl azide (not illustrated). Manfred T. Reetz of the Max-Planck-Institut für Kohlenforschung and the Philipps-Universität Marburg found (Angew. Chem. Int. Ed. 2014, 53, 8659) that cytochrome P450 could oxidize the cyclohexane 23 to the cyclohexanol 24. F. Dean Toste of the University of California, Berkeley aminated (J. Am. Chem. Soc. 2015, 137, 3205) the ketone 25 with 26 to give 27. Benjamin List, also of the Max-Planck-Institut für Kohlenforschung, reported (Synlett 2015, 26, 1413) a parallel investigation. Philip Kraft of Givaudan Schweiz AG and Professor List added (Angew. Chem. Int. Ed. 2015, 54, 1960) 28 to 29 to give 30 in high ee.

Flow Chemistry: The Direct Production of Drug Metabolites

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Organic Synthesis ◽  
Flow Chemistry ◽  
Florida State University ◽  
State University ◽  
Max Planck ◽  
Direct Production ◽  
Reactor Technology ◽  
University Of Cambridge ◽  
The University

Several overviews of flow chemistry appeared recently. Katherine S. Elvira and Andrew J. deMello of ETH Zürich wrote (Nature Chem. 2013, 5, 905) on micro­fluidic reactor technology. D. Tyler McQuade of Florida State University and the Max Planck Institute Mühlenberg reviewed (J. Org. Chem. 2013, 78, 6384) applications and equipment. Jun-ichi Yoshida of Kyoto University focused (Chem. Commun. 2013, 49, 9896) on transformations that cannot be effected under batch condi­tions. Detlev Belder of the Universität Leipzig reported (Chem. Commun. 2013, 49, 11644) flow reactions coupled to subsequent micropreparative separations. Leroy Cronin of the University of Glasgow described (Chem. Sci. 2013, 4, 3099) combin­ing 3D printing of an apparatus and liquid handling for convenient chemical synthe­sis and purification. Many of the reactions of organic synthesis have now been adapted to flow con­ditions. We will highlight those transformations that incorporate particularly useful features. One of those is convenient handling of gaseous reagents. C. Oliver Kappe of the Karl-Franzens-University Graz generated (Angew. Chem. Int. Ed. 2013, 52, 10241) diimide in situ to reduce 1 to 2. David J. Cole-Hamilton immobilized (Angew. Chem. Int. Ed. 2013, 52, 9805) Ru DuPHOS on a heteropoly acid support, allowing the flow hydrogenation of neat 3 to 4 in high ee. Steven V. Ley of the University of Cambridge added (Org. Process Res. Dev. 2013, 17, 1183) ammonia to 5 to give the thiourea 6. Alain Favre-Réguillon of the Conservatoire National des Arts et Métiers used (Org. Lett. 2013, 15, 5978) oxygen to directly oxidize the aldehyde 7 to the car­boxylic acid 8. Professor Kappe showed (J. Org. Chem. 2013, 78, 10567) that supercritical ace­tonitrile directly converted an acid 9 to the nitrile 10. Hisao Yoshida of Nagoya University added (Chem. Commun. 2013, 49, 3793) acetonitrile to nitrobenzene 11 to give the para isomer 12 with high regioselectively. Kristin E. Price of Pfizer Groton coupled (Org. Lett. 2013, 15, 4342) 13 to 14 to give 15 with very low loading of the Pd catalyst. Andrew Livingston of Imperial College demonstrated (Org. Process Res. Dev. 2013, 17, 967) the utility of nanofiltration under flow conditions to minimize Pd levels in a Heck product.

Becoming A Geologist: Florence Bascom and Johns Hopkins, 1888-1895

2000 ◽  
Vol 19 (1) ◽  
pp. 2-25 ◽  
Author(s):  
Lois Arnold
Keyword(s):  
Bryn Mawr ◽  
Field Work ◽  
Laboratory Research ◽  
State University ◽  
University Of Michigan ◽  
Master Of Science ◽  
University Of Wisconsin ◽  
Experience Teaching ◽  
Johns Hopkins University ◽  
The University

Florence Bascom (1862-1945) was a petrologist and field geologist at Bryn Mawr College who provided a basic description and interpretation of major areas of Pennsylvania and surrounding regions. This paper is the second of a two-part study that explores the question of how Bascom became a geologist. The first part dealt with Bascom's early history in Wisconsin, from the time she went to Madison at the age of 12 to her completion of a Master of Science degree in Microscopic Lithology under Roland D. Irving (1847-1888) at the University Of Wisconsin in 1887.This second part of the study begins with Bascom's experience teaching at Rockford Seminary in Illinois, where she was exposed to Mary E. Holmes (1850-1906). who had obtained a doctorate in paleontology from the University of Michigan. It then details the extension of Bascom's education from a limited laboratory-based experience to involvement in field work with George Huntington Williams (1856-1894) at Johns Hopkins University in the years 1891-1893. Johns Hopkins did not officially admit women to graduate study then. Nevertheless, on the basis of combined field and laboratory research in the Monterey district of Pennsylvania, Bascom received the first doctorate granted to a woman at the University. She was then hired as an Assistant in Geology by Edward Orton (1829-1899), at Ohio State University, a highly unusual appointment at that time. In addition to teaching, she was engaged in field and laboratory work at Ohio State until 1895, when she was hired by Martha Carey Thomas (1857-1935) at Bryn Mawr.

Heteroaromatic Synthesis: The Tokuyama Synthesis of (−)-Rhazinilam

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Ni Catalyst ◽  
State University ◽  
Colorado State University ◽  
Ru Catalyst ◽  
Opioid Ligands ◽  
University Of Wisconsin ◽  
Rh Catalyst ◽  
Indian Institute Of Science ◽  
The University ◽  
École Polytechnique

Mei-Huey Lin of the National Changhua University of Education rearranged (J. Org. Chem. 2014, 79, 2751) the initial allene derived from 1 to the γ-chloroenone. Displacement with acetate followed by hydrolysis led to the furan 2. A. Stephen K. Hashmi of Ruprecht-Karls-Universität Heidelberg showed (Angew. Chem. Int. Ed. 2014, 53, 3715) that the Au-catalyzed conversion of the bis alkyne 3, mediated by 4, proceeded selectively to give 5. Tehshik P. Yoon of the University of Wisconsin used (Angew. Chem. Int. Ed. 2014, 53, 793) visible light with a Ru catalyst to rearrange the azide 6 to the pyrrole 7. Cheol-Min Park, now at UNIST, found (Chem. Sci. 2014, 5, 2347) that a Ni catalyst reorganized the methoxime 8 to the pyrrole 9. A Rh catalyst converted 8 to the corresponding pyridine (not illustrated). In the course of a synthesis of opioid ligands, Kenner C. Rice of the National Institute on Drug Abuse optimized (J. Org. Chem. 2014, 79, 5007) the preparation of the pyridine 11 from the alcohol 10. Vincent Tognetti and Cyrille Sabot of the University of Rouen heated (J. Org. Chem. 2014, 79, 1303) 12 and 13 under micro­wave irradiation to give the 3-hydroxy pyridine 14. Tomislav Rovis of Colorado State University prepared (J. Am. Chem. Soc. 2014, 136, 2735) the pyridine 17 by the Rh-catalyzed combination of 15 with 16. Fabien Gagosz of the Ecole Polytechnique rearranged (Angew. Chem. Int. Ed. 2014, 53, 4959) the azirine 18, readily available from the oxime of the β-keto ester, to the pyridine 19. Matthias Beller of the Universität Rostock used (Chem. Eur. J. 2014, 20, 1818) a Zn catalyst to mediate the opening of the epoxide 21 with the aniline 20. A Rh cata­lyst effected the oxidation and cyclization of the product amino alcohol to the indole 22. Sreenivas Katukojvala of the Indian Institute of Science Education & Research showed (Angew. Chem. Int. Ed. 2014, 53, 4076) that the diazo ketone 23 could be used to anneal a benzene ring onto the pyrrole 24, leading to the 2,7-disubstituted indole 25.

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