Metal Mediated C-C Ring Construction:The Nevado Route to (-)- Frondosin A

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Oxidative Coupling ◽  
Gold Catalyst ◽  
University Of California ◽  
Terminal Alkyne ◽  
University Of Utah ◽  
University Of Wisconsin ◽  
Peking University ◽  
University Of Zurich ◽  
The University ◽  
University Of Manchester

Barry M. Trost of Stanford University generated (J. Am. Chem. Soc. 2011, 133, 4766) a β-keto carbene from the propargyl alcohol 1, leading to the cyclopropane 2. Tsutomu Katsuki of Kyushu University devised (J. Am. Chem. Soc. 2011, 133, 170) an Ir catalyst for the enantioselective cyclopropenation of a terminal alkyne 3 to give 5. David J. Procter of the University of Manchester showed (Org. Lett. 2010, 12, 5446) that the SmI2 -mediated cyclization of 6 proceeded with high diastereocontrol. F. Dean Toste of the University of California, Berkeley, developed (J. Am. Chem. Soc. 2011, 133, 5500) a gold catalyst for the enantioselective cyclization of 8 to 9. Jon D. Rainier of the University of Utah found (Org. Lett. 2011, 13, 700) that the readily prepared diazo ester 10 cyclized smoothly to 11. Brian M. Stoltz of Caltech rearranged (Angew. Chem. Int. Ed. 2011, 50, 2756) 12, prepared by enantioselective allylation, to the cyclopentene 13. Tushar Kanti Chakraborty of the Indian Institute of Chemical Technology cyclized (Tetrahedron Lett. 2011, 52, 1709) the epoxy ester 14 to the cyclopentanol 15. Zhi-Xiang Yu of Peking University found (Angew. Chem. Int. Ed. 2011, 50, 2144) that a BINOL-derived catalyst cyclized 16 to 17. Related transition metal-mediated cyclizations (not illustrated) have been reported (Org. Lett. 2011, 13, 1517, 2630). Pher G. Andersson of Uppsala University reduced (Chem. Commun. 2011, 47, 3989) the inexpensive Birch reduction product 18 to give, after hydrolysis, the cyclohexanone 19 in high ee. Silas P. Cook of the University of Indiana found (Org. Lett. 2011, 13, 1904) conditions for the allylation of the Zn enolate resulting from enantioselective conjugate addition to cyclohexenone 20. This approach worked for other ring sizes as well. Weiping Tang of the University of Wisconsin effected (Angew. Chem. Int. Ed. 2011, 50, 1346) regioselective cyclocarbonylation of 22 to give the cyclohexanone 23. Ken Tanaka of the Tokyo University of Agriculture and Technology devised (Angew. Chem. Int. Ed. 2011, 50, 1664) a spectacular three-component coupling leading, after oxidative coupling, to the cyclohexane 26. Cristina Nevada of the University of Zurich condensed (Angew. Chem. Int. Ed. 2011, 50, 911) 27 with 28 to give, after methanolysis, the cycloheptanone 29 in high ee.

Metal-Mediated Carbocyclic Construction:The Kobayashi Synthesis of (+)-Fomitellic Acid B

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Gold Catalyst ◽  
Ni Catalyst ◽  
University Of Utah ◽  
Keto Esters ◽  
Wayne State University ◽  
Cu Catalyst ◽  
Rh Catalyst ◽  
La Jolla ◽  
The University ◽  
University Of Manchester

Jin K. Cha of Wayne State University described (J. Org. Chem. 2009, 74, 5528) the diastereoselective intramolecular cyclopropanation of nitriles with homoallylic alcohols such as 1 . Valery V. Fokin of Scripps/La Jolla found (J. Am. Chem. Soc. 2009, 131, 18034) that the diazoimine derived from 4 could add with high enantioselectivity to aryl alkenes, including styrene 5. Andreas Gansäuer of the University of Bonn optimized (Angew. Chem. Int. Ed. 2009, 48 , 8882; Tetrahedron 2009, 65, 10791) the Ti catalyst to enable efficient cyclization of substrates such as 7 to the corresponding cyclobutanes. F. Dean Toste of the University of California, Berkeley, devised (J. Am. Chem. Soc. 2009, 131, 9178) a gold catalyst for the enantioselective ring expansion of a prochiral allene such as 9 to the cyclobutanone 10. David J. Procter of the University of Manchester developed (J. Am. Chem. Soc. 2009, 131, 15467) the SmI2 -mediated cyclization of a lactone such as 11 to the cyclopentanone 12. Shigeki Matsunaga and Masakatsu Shibasaki of the University of Tokyo designed (Chem. Commun. 2009, 5138) a Ni catalyst for the enantioselective condensation of 13 with formaldehyde. Some acyclic β-keto esters could also be hydroxymethylated with high enantiocontrol. Darren J. Dixon, also of the University of Manchester, devised (J. Am. Chem. Soc. 2009, 131, 9140) a Cu catalyst for the enantioselective Conia cyclization of 15 to 16 . K. C. Nicolaou, also of Scripps/La Jolla, reported (Angew. Chem. Int. Ed. 2009, 48, 6293) a Rh catalyst for the related cyclization of 17 to 18. Ryo Shintani and Tamio Hayashi of Kyoto University showed (J. Am. Chem. Soc. 2009, 131, 13588) that a Rh catalyst could effect enantioselective conjugate addition of a tetraaryl borate even to a 3-methyl cyclohexenone 19, to establish the cyclic quaternary center. Alexandre Alexakis of the University of Geneva established (Chem. Commun . 2009, 3868) that with the easily ionized allylic bromide 21, Cu-mediated coupling with the alkyl Grignard 22 proceeded with substantial asymmetric induction. Jon D. Rainier of the University of Utah devised (Organic Lett. 2009, 11, 38774) conditions for effecting Ti-mediated intramolecular metathesis between an alkene and a lactam carbonyl, giving the cyclic enamide 24.

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.

bell hooks

2020 ◽  
pp. 708-712
Keyword(s):  
High School ◽  
African American ◽  
University Of California ◽  
Stanford University ◽  
Santa Cruz ◽  
Bell Hooks ◽  
Segregated Schools ◽  
University Of Wisconsin ◽  
The University

Writer, educator, and feminist bell hooks was born Gloria Jean Watkins in Hopkinsville, Kentucky. After initially attending segregated schools, hooks, who is African American, graduated from an integrated high school. She earned a BA from Stanford University, an MA from the University of Wisconsin, Madison, and a PhD from the University of California, Santa Cruz. hooks adopted her pen name from the name of her maternal great-grandmother, Bell Blair Hooks, a woman known for her bold speech....

Alkenes

2017 ◽  
Author(s):  
Allison K. Griffith ◽  
Tristan H. Lambert
Keyword(s):  
State University ◽  
One Pot ◽  
Colorado State University ◽  
University Of Oxford ◽  
University Of British Columbia ◽  
University Of Wisconsin ◽  
Unsaturated Carbonyl Compound ◽  
Institute Of Technology ◽  
University Of Zurich ◽  
The University

The α-C–H functionalization of piperidine catalyzed by tantalum complex 1 to pro­duce amine 2 was developed (Org. Lett. 2013, 15, 2182) by Laurel L. Schafer at the University of British Columbia. An asymmetric diamination of diene 3 with diaziri­dine reagent 4 under palladium catalysis to furnish cyclic sulfamide 5 was developed (Org. Lett. 2013, 15, 796) by Yian Shi at Colorado State University. Enantioenriched β-fluoropiperdine 8 was prepared (Angew. Chem. Int. Ed. 2013, 52, 2469) via amino­fluorocyclization of 6 with hypervalent iodide 7, as reported by Cristina Nevado at the University of Zurich. Erick M. Carreira at ETH Zürich disclosed (J. Am. Chem. Soc. 2013, 135, 6814) a ruthenium-catalyzed hydrocarbamoylation of allylic formamide 9 to yield pyrrolidone 10. Hans-Günther Schmalz at the University of Köln disclosed (Angew. Chem. Int. Ed. 2013, 52, 1576) an asymmetric hydrocyanation of styrene 11 with Ni(cod)₂ and phosphine–phosphite ligand 12 to yield exclusively the branched cyanide 13. A simi­lar transformation of styrene 11 to the hydroxycarbonylated product 15 was catalyzed (Chem. Commun. 2013, 49, 3306) by palladium complex 14, as reported by Matthew L. Clarke at the University of St Andrews. Feng-Ling Qing at the Chinese Academy of Sciences found (Angew. Chem. Int. Ed. 2013, 52, 2198) that the hydrotrifluoromethylation of unactivated alkene 16 to 17 was catalyzed by silver nitrate. The same transformation was also reported (J. Am.Chem. Soc. 2013, 135, 2505) by Véronique Gouverneur at the University of Oxford using a ruthenium photocatalyst and the Umemoto reagent 18. Clark R. Landis at the University of Wisconsin, Madison reported (Angew. Chem. Int. Ed. 2013, 52, 1564) a one-pot asymmetric hydroformylation using 21 followed by Wittig olefination to transform alkene 19 into the γ-chiral α,β-unsaturated carbonyl compound 20. Debabrata Mati at the Indian Institute of Technology Bombay found (J. Am. Chem. Soc. 2013, 135, 3355) that alkene 22 could be nitrated stereoselectively with silver nitrite and TEMPO to form alkene 23. Damian W. Young at the Broad Institute disclosed (Org. Lett. 2013, 15, 1218) that a macrocyclic vinylsiloxane 24, which was synthesized via an E-selective ring clos­ing metathesis reaction, could be functionalized to make either E- or Z-alkenes, 25 and 26.

New Methods for C–N Ring Construction

2015 ◽  
Author(s):  
Tristan H. Lambert
Keyword(s):  
New York ◽  
Gold Catalyst ◽  
Earth Metal ◽  
Allylic Alcohols ◽  
State University ◽  
University Of Oxford ◽  
University Of Wisconsin ◽  
Vinyl Iodide ◽  
Hydride Elimination ◽  
The University

The reduction of pyridines offers an attractive approach to piperidine synthesis, and now Toshimichi Ohmura and Michinori Suginome of Kyoto University have developed (J. Am. Chem. Soc. 2012, 134, 3699) a rhodium-catalyzed hydroboration of pyridines, including the reaction of 1 to produce 3. Timothy J. Donohoe at the University of Oxford has found (Org. Lett. 2011, 13, 2074) that pyridinium silanes 4 undergo intramolecular hydride transfer by treatment with TBAF to produce dihydropyridones (e.g., 5) with good diastereoselectivity. Enantioselective amination of allylic alcohols has proven challenging, but Ross A. Widenhoefer at Duke University has reported (Angew. Chem. Int. Ed. 2012, 51, 1405) that a chiral gold catalyst can effect such intramolecular cyclizations with good enantioselectivity, as in the synthesis of 7 from 6. Alternatively, Masato Kitamura at Nagoya University has developed (Org. Lett. 2012, 14, 608) a ruthenium catalyst that operates at as low as 0.05 mol% loading for the conversion of substrates such as 8 to 9. Efforts to replace transition metal catalysts with alkaline earth metal-based alternatives have been gaining increasing attention, and Kai C. Hultzsch at Rutgers University has found (Angew. Chem. Int. Ed. 2012, 51, 394) that the magnesium complex 12 is capable of catalyzing intramolecular hydroamination (e.g., 10 to 11) with high enantioselectivity. Meanwhile, a stereoselective Wacker-type oxidation of tert-butanesulfinamides such as 13 to produce pyrrolidine derivatives 14 has been disclosed (Org. Lett. 2012, 14, 1242) by Shannon S. Stahl at the University of Wisconsin at Madison. Though highly desirable, Heck reactions have rarely proven feasible with alkyl halides due to competitive β-hydride elimination of the alkyl palladium intermediates. Sherry R. Chemler at the State University of New York at Buffalo has demonstrated (J. Am. Chem. Soc. 2012, 134, 2020) a copper-catalyzed enantioselective amination Heck-type cascade (e.g., 15 and 16 to 17) that is thought to proceed via radical intermediates. David L. Van Vranken at the University of California at Irvine has reported (Org. Lett. 2012, 14, 3233) the carbenylative amination of N-tosylhydrazones, which proceeds through η3-allyl Pd intermediates constructed via carbene insertion. This chemistry was applied to the two-step synthesis of caulophyllumine B from vinyl iodide 18 and N-tosylhydrazone 19.

scholarly journals Geographer, historian and classic French regionalist: The evolution of the writings of Jean Gottmann

2003 ◽  
Vol 70 (418/419) ◽  
pp. 13-18
Author(s):  
Robert A. Harper
Keyword(s):  
Professor Emeritus ◽  
National Council ◽  
Geographic Education ◽  
Past President ◽  
University Of Maryland ◽  
Maryland College ◽  
Peking University ◽  
College Park ◽  
The University ◽  
University Of Manchester

The author, Professor Emeritus of Geography, University of Maryland, College Park, holds four degrees from the University of Chicago and is the recipient of the University's Distinguished Alumnus award. A close associate of Jean Gottmann, he co-edited two volumes - Metropolis on the Move and Since Megalopolis with him. Harper's urban interest primarily concerns cities as central places and city networks. He also edited Modern Metropolitan Systems with Charles Christian. He has keen interest in geographic education. He is past president of the National Council for Geographic Education and recipient of their George J. Miller Award. He has written world geography texts for students from elementary school to college. He has been a visiting professor at the University of Manchester, University of Sydney, University of Durban-Westville, and Peking University.

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.

Organic Functional Group Protection

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Oxidative Coupling ◽  
Indian Institute ◽  
Secondary Amide ◽  
Smith College ◽  
University Of Technology ◽  
Northwestern University ◽  
The University ◽  
University Of Manchester ◽  
Hydrolysis Of ◽  
Sulfonyl Fluoride

Dithianes such as 1 are readily prepared, from the corresponding ketone or by alkyl­ation. Masayuki Kirihara of the Shizuoka Institute of Science and Technology devel­oped (Tetrahedron Lett. 2013, 54, 5477) an oxidative method for the deprotection of 1 to 2. Konrad Tiefenbacher of the Technische Universität München devised (J. Am. Chem. Soc. 2013, 135, 16213) a hexameric resorcinarene capsule that selectively catalyzed the hydrolysis of the smaller acetal 3 to 4 in the presence of a longer chain acetal. David J. Gorin of Smith College reported (J. Org. Chem. 2013, 78, 11606) the methylation of an acid 5 to 6 using dimethyl carbonate as the donor. Two peroxide-based methods (J. Org. Chem. 2013, 78, 9898; Org. Lett. 2013, 15, 3326) for carboxylic acid methylation (not illustrated) were also recently described. Hisashi Yamamoto of the University of Chicago showed (Angew. Chem. Int. Ed. 2013, 52, 7198) that the “supersilyl” ester 8, prepared from 7, was stable enough to be deprotonated and alkyl­ated, but was easily removed. Michal Szostak and David J. Procter of the University of Manchester uncovered (Angew. Chem. Int. Ed. 2013, 52, 7237) the remarkable cleavage of a C–N bond in an amide 9, leading to the secondary amide 10. This could offer an alternative strategy for difficult-to-hydrolyze amides. Richard B. Silverman of Northwestern University described (J. Org. Chem. 2013, 78, 10931) improved protocols for the formation and removal of the N-protecting 2,5-dimethylpyrrole 11 to give 12. Huanfeng Jiang of the South China University of Technology showed (Chem. Commun. 2013, 49, 6102) that an arenesulfonamide 14 can be prepared by oxidation of the corresponding sodium arenesulfinate 13. Douglas A. Klumpp of Northern Illinois University prepared (Tetrahedron Lett. 2013, 54, 5945) sul­fonamides (not illustrated) by combining a sulfonyl fluoride with a silyl amine. K. Rajender Reddy of the Indian Institute of Chemical Technology developed (Chem. Commun. 2013, 49, 6686) a new route to a urea 17, by oxidative coupling of an amine 15 with a formamide 16.

Reactions of Alkenes

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
South China ◽  
Diazonium Salt ◽  
Solvent Free ◽  
University Of California ◽  
University Of Wisconsin ◽  
University Of Technology ◽  
Complementary Approach ◽  
Re Catalyst ◽  
La Jolla ◽  
The University

Ana C. Fernandes of the Instituto Superior Técnico, Lisboa, devised (Tetrahedron Lett. 2010, 51, 1048) an effective Re catalyst for the solvent-free hydrogenation of an alkene 1. Yasushi Imada and Takeshi Naota of Osaka University showed (Organic Lett. 2010, 12, 32) that a flavin could catalyze the hydrogenation of an alkene 3. Note that the thioether was stable under these conditions. Huanfeng Jian of the South China University of Technology developed (J. Org. Chem. 2010, 75, 2321) a Pd-based protocol for the oxidative cleavage of an alkene 5. The cleavage could be halted at the cis diol. K. C. Nicolaou of Scripps/La Jolla optimized (Organic Lett. 2010, 12, 1552) a complemetary cleavage of an alkene 7, again proceeding via the diol. J. R. Falck of UT Southwestern established (J. Org. Chem. 2010, 75, 1701) the Heck-type oxidative silylation of an alkene 9 to the Z -silane 10. Timothy F. Jamison of MIT effected (Chem. Commun. 2010, 46, 907) the borylation of an alkene 11. Kálmán Szabó of Stockholm University reported (Angew. Chem. Int. Ed. 2010, 49, 4051) a complementary approach for effecting the same transformation. Cathleen M. Crudden of Queen’s University, Kingston, observed (J. Am. Chem. Soc. 2010, 132, 131) that Rh-catalyzed hydroboration of 13 delivered the borane 14. Tehshik P. Yoon of the University of Wisconsin used (J. Am. Chem. Soc. 2010, 132, 4570) Fe to catalyze the addition of an oxaziridine 16 to an alkene 15. Yasuhiro Shiraishi of Osaka University improved (J. Org. Chem. 2010, 75, 1450) the photochemical addition of acetone to an alkene 18. Chul-Ho Jun of Yonsei University described (Tetrahedron Lett. 2010, 51, 160) a related procedure. Professor Jamison effected (J. Am. Chem. Soc. 2010, 132, 6880) the branching homologation of an alkene to give 21 . F. Dean Toste of the University of California, Berkeley, accomplished (J. Am. Chem. Soc. 2010, 132, 8885) the oxidative homologation of an alkene to the ester 22. Markus R. Heinrich of the Universität Erlangen-Nürnberg developed (Tetrahedron Lett. 2010, 51, 1758) the tandem addition of the hydroperoxide 23 and a diazonium salt 24, leading to 25.

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