Substituted Benzenes: The Li Synthesis of Rubriflordilactone A

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Diels Alder ◽  
University Of California ◽  
Indiana University ◽  
Tsinghua University ◽  
College Of Technology ◽  
Osaka Prefecture ◽  
Crude Reaction Mixture ◽  
Institute Of Technology ◽  
The University

Cheol-Hong Cheon of Korea University (J. Org. Chem. 2014, 79, 7277) and Toshiyuki Kamei and Toyoshi Shimada of the Nara National College of Technology (Tetrahedron Lett. 2014, 55, 4245) described the ring bromination of arene boronates. The boronate can then be removed, enabling the conversion of 1 to 2. Yu Rao of Tsinghua University constructed (Chem. Commun. 2014, 50, 15037) the sulfone 5 by coupling the arenes 3 and 4 with K2S2O8. Igor Larrosa of Queen Mary University of London assembled (Chem. Sci. 2014, 5, 3509) the biphenyl 8 by arylating 6 with the iodide 7. Guy Bertrand of the University of California, San Diego showed (J. Am. Chem. Soc. 2014, 136, 13594) that under Au catalysis, the aniline 9 was sufficiently nucleophilic to add in a conjugate sense to the enone 10 to give 11. Hideo Togo of Chiba University optimized (Eur. J. Org. Chem. 2014, 6077) condi­tions for the selective ortho formylation of a phenol 12. The crude reaction mixture could also be directly oxidized with I2/ NH3 to give the nitrile 13. Silas P. Cook of Indiana University ortho metalated (J. Am. Chem. Soc. 2014, 136, 13130; Angew. Chem. Int. Ed. 2014, 53, 11065) the benzamide 14, then used an iron catalyst to couple that intermediate with a halide 15, leading to the alkylated product 16. As with the phenol 12 and the benzamide 14, aromatic functionalization has usu­ally been directed by a functional group directly attached to the ring. Daqin Shi and Yingsheng Zhao of Soochow University showed (Chem. Sci. 2014, 5, 4962) that a longer tether can be effective, as illustrated by the conversion of 17 to 19. Debabrata Maiti of the Indian Institute of Technology Bombay also used (Org. Lett. 2014, 16, 5760) a longer tether for the selective meta functionalization of 20 to 22. Motohiro Sonoda of Osaka Prefecture University constructed (Tetrahedron Lett. 2014, 55, 5302) the phenol 25 by acid-mediated rearrangement of the Diels–Alder adduct of 24 with the furan 23. Anthony G. M. Barrett of Imperial College London devised (J. Org. Chem. 2014, 79, 8706) conditions for the iodinative cyclization of 26 to 27.

Using Mammon for Righteousness

2017 ◽  
Author(s):  
Joan Marie Johnson
Keyword(s):  
University Of California ◽  
Massachusetts Institute ◽  
Massachusetts Institute Of Technology ◽  
Access To Education ◽  
Intellectual Achievement ◽  
Institute Of Technology ◽  
The University

Chapter 5 explores what happened when women approached existing coeducational schools offering restricted gifts to benefit women. These donations either forced a school to open its doors to women or increased the number of women admitted by providing scholarships for women or erecting a women’s building or a women’s dormitory. Like the college founders, these donors believed that women were capable of the same intellectual achievement as men but found that many of America’s best universities resisted coeducation. The women in this chapter, including Mary Garrett, and Phoebe Hearst and the gifts they gave show how money could be wielded to force changes that would benefit women, in the form of access to education and professions formerly restricted to men. Moreover, coeducation at these schools, including Johns Hopkins, Massachusetts Institute of Technology, and the University of California, Berkeley, was especially significant. If women were welcomed at these important institutions, they could demonstrate their intellectual and professional capabilities and equality with men.

scholarly journals Meet the APSA Council and Officers

2012 ◽  
Vol 45 (01) ◽  
pp. 151-154
Keyword(s):  
Harvard University ◽  
University Of California ◽  
Massachusetts Institute ◽  
University Of Southern California ◽  
Massachusetts Institute Of Technology ◽  
New Members ◽  
Reed College ◽  
Institute Of Technology ◽  
The University ◽  
University Of Manchester

As noted in the October issue ofPS, G. Bingham Powell, Jr., the Marie E .and Joseph C. Wilson Professor of Political Science at the University of Rochester, became APSA's 108th president on September 4, 2011, at the close of the APSA Annual Meeting. Eight new members of the APSA council were elected fall 2011. The new members are Paul Gronke, Reed College; Ange-Marie Hancock, University of Southern California; David A. Lake, University of California, San Diego; Taeku Lee, University of California, Berkeley; Kenneth J. Meier, Texas A&M University; Kathleen Thelen, Massachusetts Institute of Technology; Stephen M. Walt, Harvard University; and Angelia R. Wilson, University of Manchester.

Diels–Alder Cycloaddition: Sarcandralactone A (Snyder), Pseudopterosin (−)-G-J Aglycone (Paddon-Row/Sherburn), IBIR-22 (Westwood), Muironolide A (Zakarian), Platencin (Banwell), Chatancin (Maimone)

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Absolute Configuration ◽  
Alder Reaction ◽  
Diels Alder ◽  
University Of California ◽  
Enantiomerically Pure ◽  
Protein Protein Interaction ◽  
South Wales ◽  
National University ◽  
The Absolute ◽  
The University

En route to sarcandralactone A 3, Scott A. Snyder of Scripps Florida effected (Angew. Chem. Int. Ed. 2015, 54, 7842) Diels–Alder cycloaddition of the activated enone 1 to the Danishefsky diene. On exposure to trifluoroacetic acid, the adduct was unraveled to the ene dione 2. Michael N. Paddon-Row of the University of New South Wales and Michael S. Sherburn of the Australian National University prepared (Nature Chem. 2015, 7, 82) the allene 4 in enantiomerically-pure form. Sequential cycloaddition with 5 followed by 6 gave an adduct that was decarbonylated to 7. Further cycloaddition with nitro­ethylene 8 led to the pseudopterosin (−)-G-J aglycone 9. The protein–protein interaction inhibitor JBIR-22 12 contains a quaternary α-amino acid pendant to a bicyclic core. Nicholas J. Westwood of the University of St. Andrews set (Angew. Chem. Int. Ed. 2015, 54, 4046) the absolute configuration of the core 11 by using an organocatalyst to activate the cyclization of 10. Metal catalysts can also be used to set the absolute configuration of a Diels–Alder cycloaddition. In the course of establishing the structure of the marine natural prod­uct muironolide A 15, Armen Zakarian of the University of California, Santa Barbara cyclized (J. Am. Chem. Soc. 2015, 137, 5907) the enol form of 13 preferentially to the diastereomer 14. Unactivated intramolecular Diels–Alder cycloadditions have been carried out with more and more challenging substrates. A key step in the synthesis (Chem. Asian. J. 2015, 10, 427) of (−)-platencin 18 by Martin G. Banwell, also of the Australian National University, was the cyclization of 16 to 17. In another illustration of the power of the unactivated intramolecular Diels–Alder reaction, Thomas J. Maimone of the University of California, Berkeley cyclized (Angew. Chem. Int. Ed. 2015, 54, 1223) the tetraene 19 to the tricycle 20. Allylic chlo­rination followed by reductive cyclization converted 20 to chatancin 21.

Reactions of Alkenes

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Catalytic Reduction ◽  
Indian Institute ◽  
Yale University ◽  
Terminal Alkene ◽  
National University ◽  
Institute Of Technology ◽  
La Jolla ◽  
The University

The catalytic reduction of the alkene 1 gave the cis-fused product (not illustrated), by kinetic H₂ addition to the less congested face of the alkene. Ryan A. Shenvi of Scripps La Jolla found (J. Am. Chem. Soc. 2014, 136, 1300) conditions for stepwise HAT, con­verting 1 to the thermodynamically-favored trans-fused ketone 2. Seth B. Herzon of Yale University devised (J. Am. Chem. Soc. 2014, 136, 6884) a protocol for the reduc­tion, mediated by 4, of the double bond of a haloalkene 3 to give the saturated halide 5. The Shenvi conditions also reduced a haloalkene to the saturated halide. Daniel J. Weix of the University of Rochester and Patrick L. Holland, also of Yale University, established (J. Am. Chem. Soc. 2014, 136, 945) conditions for the kinetic isomerization of a terminal alkene 6 to the Z internal alkene 7. Christoforos G. Kokotos of the University of Athens showed (J. Org. Chem. 2014, 79, 4270) that the ketone 9, used catalytically, markedly accelerated the Payne epoxidation of 8 to 10. Note that Helena M. C. Ferraz of the Universidade of São Paulo reported (Tetrahedron Lett. 2000, 41, 5021) several years ago that alkene epoxidation was also easily carried out with DMDO generated in situ from acetone and oxone. Theodore A. Betley of Harvard University prepared (Chem. Sci. 2014, 5, 1526) the allylic amine 12 by reacting the alkene 11 with 1-azidoadamantane in the presence of an iron catalyst. Rodney A. Fernandes of the Indian Institute of Technology Bombay developed (J. Org. Chem. 2014, 79, 5787) efficient conditions for the Wacker oxida­tion of a terminal alkene 6 to the methyl ketone 13. Yong-Qiang Wang of Northwest University oxidized (Org. Lett. 2014, 16, 1610) the alkene 6 to the enone 14. Peili Teo of the National University of Singapore devised (Chem. Commun. 2014, 50, 2608) conditions for the Markovnikov hydration of the alkene 6 to the alcohol 15. Internal alkenes were inert under these conditions, but Yoshikazo Kitano of the Tokyo University of Agriculture and Technology effected (Synthesis 2014, 46, 1455) the Markovnikov amination (not illustrated) of more highly substituted alkenes.

Functional Group Protection: The Pohl Synthesis of β-1,4-Mannuronate Oligomers

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Iron Catalyst ◽  
Gold Catalyst ◽  
State University ◽  
Allyl Ester ◽  
National Chemical Laboratory ◽  
Chemical Laboratory ◽  
Benzyl Ethers ◽  
Institute Of Technology ◽  
Tokyo Medical ◽  
The University

D. Srinivasa Reddy of the National Chemical Laboratory converted (Org. Lett. 2015, 17, 2090) the selenide 1 to the alkene 2 under ozonolysis conditions. Takamitsu Hosoya of the Tokyo Medical and Dental University found (Chem. Commun. 2015, 51, 8745) that even highly strained alkynes such as 4 can be generated from a sulfinyl vinyl triflate 3. An alkyne can be protected as the dicobalt hexacarbonyl complex. Joe B. Gilroy and Mark S. Workentin of the University of Western Ontario found (Chem. Commun. 2015, 51, 6647) that following click chemistry on a non-protected distal alkyne, deprotection of 5 to 6 could be effected by exposure to TMNO. Stefan Bräse of the Karlsruhe Institute of Technology and Irina A. Balova of Saint Petersburg State University showed (J. Org. Chem. 2015, 80, 5546) that the bend of the Co complex of 7 enabled ring-closing metathesis, leading after deprotection to 8. Morten Meldal of the University of Copenhagen devised (Eur. J. Org. Chem. 2015, 1433) 9, the base-labile protected form of the aldehyde 10. Nicholas Gathergood of Dublin City University and Stephen J. Connon of the University of Dublin developed (Eur. J. Org. Chem. 2015, 188) an imidazolium catalyst for the exchange deprotection of 11 to 13, with the inexpensive aldehyde 12 as the acceptor. Peter J. Lindsay-Scott of Eli Lilly demonstrated (Org. Lett. 2015, 17, 476) that on exposure to KF, the isoxa­zole 14 unraveled to the nitrile 15. Masato Kitamura of Nagoya University observed (Tetrahedron 2015, 71, 6559) that the allyl ester of 16 could be removed to give 17, with the other alkene not affected. Benzyl ethers are among the most common of alcohol protecting groups. Yongxiang Liu and Maosheng Cheng of Shenyang Pharmaceutical University showed (Adv. Synth. Catal. 2015, 357, 1029) that 18 could be converted to 19 simply by expo­sure to benzyl alcohol in the presence of a gold catalyst. Reko Leino of Åbo Akademi University developed (Synthesis 2015, 47, 1749) an iron catalyst for the reductive benzylation of 20 to 21. Related results (not illustrated) were reported (Org. Lett. 2015, 17, 1778) by Chae S. Yi of Marquette University.

Diels-Alder Cycloaddition: Fawcettimine (Williams), Apiosporic Acid (Helmchen), Marginatone (Abad- Somovilla), Okilactomycin (Hoye), Vinigrol (Barriault), Plakotenin (Bihlmeier/Klopper)

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Natural Product ◽  
Diels Alder ◽  
State University ◽  
University Of Minnesota ◽  
Enantiomerically Pure ◽  
Colorado State University ◽  
Institute Of Technology ◽  
La Jolla ◽  
The University ◽  
Stereogenic Center

Highly substituted dienes and dienophiles are often reluctant participants in intermolecular Diels-Alder cycloaddition. Nevertheless, Robert M. Williams of Colorado State University, in the course of a synthesis of fawcettimine 4, was able (J. Org. Chem. 2012, 77, 4801) to prepare 3 by combining the enone 1 with the diene 2. Günter Helmchen of the Universität Heidelberg set (J. Org. Chem. 2012, 77, 4491) the single stereogenic center of 5 by Ir-catalyzed allylic alkylation. The Lewis acid that promoted the cycloaddition also conveniently removed the trityl protecting group, leading to 6, that was saponified to apiosporic acid 7. Antonio Abad-Somovilla of the Universidad de Valencia prepared (J. Org. Chem. 2012, 77, 5664) the triene 8 in enantiomerically pure form from carvone. Despite the additional substitution on the diene, cycloaddition proceeded smoothly to give 9, which was carried on to marginatone 10. One could envision that okilactomycin 13 could be formed by an intramolecular Diels-Alder cycloaddition. Thomas R. Hoye of the University of Minnesota observed (Org. Lett. 2012, 14, 828) that the tetraene tetronic acid corresponding to 11 was inert, but that the methyl ether 11 cyclized smoothly to 12. Demethylation then gave the natural product The complex polycyclic structure of vinigrol 16 challenged organic synthesis chemists for many years, until a route was established by Phil Baran of Scripps/La Jolla (Highlights September 6, 2010). Louis Barriault cyclized (Angew. Chem. Int. Ed. 2012, 51, 2111) 14 to 15 en route to a late intermediate in the Baran synthesis It had been hypothesized that the natural product plakotenin 19 was formed naturally from a tetraene corresponding to 17. The tetraene 17 was prepared and the cyclization was successful, “confirming” both the structure of the natural product and the biosynthetic hypothesis. Angela Bihlmeier and Wim Klopper of the Karlsruhe Institute of Technology calculated (J. Am. Chem. Soc. 2012, 134, 2154) the relative energies of the four competing transition states for the cyclization, leading to a correction of the structure of 18, and so of the natural product 19.

Substituted Benzenes: The Gu Synthesis of Rhazinal

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Aryl Halide ◽  
Indian Institute ◽  
University Of California ◽  
University Of Pennsylvania ◽  
Ru Catalyst ◽  
Cu Catalyst ◽  
Institute Of Technology ◽  
The University ◽  
University Of Manchester ◽  
Structure Of Matter

Sisir K. Mandal of Asian Paints R&T Centre, Mumbai used (Tetrahedron Lett. 2013, 54, 530) a Ru catalyst to couple 2 with an electron-rich arene 1 to give 3. Jun-ichi Yoshida of Kyoto University (J. Am. Chem. Soc. 2013, 135, 5000) and John F. Hartwig of the University of California, Berkeley (J. Am. Chem. Soc. 2013, 135, 8480) also reported direct amination protocols. Tommaso Marcelli of the Politecnico di Milano and Michael J. Ingleson of the University of Manchester effected (J. Am. Chem. Soc. 2013, 135, 474) the electrophilic borylation of the aniline 4 to give 5. The regioselectivity of Ir-catalyzed borylation (J. Am. Chem. Soc. 2013, 135, 7572; Org. Lett. 2013, 15, 140) is complementary to the electrophilic process. Professor Hartwig carried (Angew. Chem. Int. Ed. 2013, 52, 933) the borylated product from 6 onto Ni-mediated coupling to give the alkylated product 7. Weiping Su of the Fujian Institute of Research on the Structure of Matter devised (Org. Lett. 2013, 15, 1718) an intriguing Pd-mediated oxidative coupling of nitroethane 9 with 8 to give 10. The coupling is apparently not proceeding via nitroethylene. Peiming Gu of Ningxia University developed (Org. Lett. 2013, 15, 1124) an azide-based cleavage that converted the aldehyde 11 into the formamide 13. Zhong-Quan Liu of Lanzhou University showed (Tetrahedron Lett. 2013, 54, 3079) that an aromatic carboxylic acid 14 could be oxidatively decarboxylated to the chloride 15. Gérard Cahiez of the Université Paris 13 found (Adv. Synth. Catal. 2013, 355, 790) mild Cu-catalyzed conditions for the reductive decarboxylation of aromatic carboxylic acids, and Debabrata Maiti of the Indian Institute of Technology, Mumbai found (Chem. Commun. 2013, 49, 252) Pd-mediated conditions for the dehydroxymethylation of benzyl alcohols (neither illustrated). Pravin R. Likhar of the Indian Institute of Chemical Technology prepared (Adv. Synth. Catal. 2013, 355, 751) a Cu catalyst that effected Castro-Stephens coupling of 16 with 17 at room temperature. Arturo Orellana of York University (Chem. Commun. 2013, 49, 5420) and Patrick J. Walsh of the University of Pennsylvania (Org. Lett. 2013, 15, 2298) showed that a cyclopropanol 20 can couple with an aryl halide 19 to give 21.

C–H Functionalization: The Maimone Synthesis of Podophyllotoxin

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
University Of California ◽  
University Of Illinois ◽  
Methyl Group ◽  
Du Bois ◽  
Princeton University ◽  
University Of Cambridge ◽  
Rh Catalyst ◽  
Institute Of Technology ◽  
La Jolla ◽  
The University

Matthias Beller of the Universität Rostock developed (Angew. Chem. Int. Ed. 2014, 53, 6477) a Rh catalyst for the acceptorless dehydrogenation of an alkane 1 to the alkene 2. Bhisma K. Patel of the Indian Institute of Technology Guwahati effected (Org. Lett. 2014, 16, 3086) oxidation of cyclohexane 3 and 4 to form the allylic benzoate 5. Justin Du Bois of Stanford University devised (Chem. Sci. 2014, 5, 656) an organocatalyst that mediated the hydroxylation of 6 to 7. Vladimir Gevorgyan of the University of Illinois, Chicago hydrosilylated (Nature Chem. 2014, 6, 122) 8 to give an intermediate that, after Ir-catalyzed intramolecular C–H functionalization followed by oxidation, was converted to the diacetate 9. Sukbok Chang of KAIST used (J. Am. Chem. Soc. 2014, 136, 4141) the methoxime of 10 to direct selective amination of the adjacent methyl group, leading to 11. John F. Hartwig of the University of California, Berkeley effected (J. Am. Chem. Soc. 2014, 136, 2555) diastereoselective Cu-catalyzed amination of 12 with 13 to make 14. David W. C. MacMillan of Princeton University accomplished (J. Am. Chem. Soc. 2014, 136, 6858) β-alkylation of the aldehyde 15 with acrylonitrile 16 to give 17. Yunyang Wei of the Nanjing University of Science and Technology alkenylated (Chem. Sci. 2014, 5, 2379) cyclohexane 3 with the styrene 18, leading to 19. Bin Wu of the Kunming Institute of Botany described (Org. Lett. 2014, 16, 480) the Pd-mediated cyclization of 20 to 21. Similar results using Cu catalysis were reported (Angew. Chem. Int. Ed. 2014, 53, 3496, 3706) by Yoichiro Kuninobu and Motomu Kanai of the University of Tokyo and by Haibo Ge of IUPUI. Jin-Quan Yu of Scripps La Jolla constructed (J. Am. Chem. Soc. 2014, 136, 5267) the lactam 24 by γ-alkenyl­ation of the amide 22 with 23, followed by cyclization. Philippe Dauban of CNRS Gif-sur-Yvette prepared (Eur. J. Org. Chem. 2014, 66) the useful crystalline chiron 27 by asymmetric amination of the enol triflate 26 with 25. Matthew J. Gaunt of the University of Cambridge showed (J. Am. Chem. Soc. 2014, 136, 8851) that the phenylative cyclization of 28 with 29 to 30 proceeded with near-perfect retention of absolute configuration.

Sign in / Sign up

Export Citation Format

Share Document