Carbon–Carbon Bond Formation: The Petrov Synthesis of Combretastatin A-4

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Good Control ◽  
Geometric Control ◽  
Pt Catalyst ◽  
University Of Mississippi ◽  
Santa Barbara ◽  
University Of Illinois ◽  
University Of Alberta ◽  
Carbon Carbon Bond ◽  
The University

Janine Cossy of ESPCI Paris (Org. Lett. 2011, 13, 4084) and Yasushi Obora of Kansai University (Chem. Lett. 2011, 40, 1055) independently developed conditions for the “borrowed hydrogen” condensation of acetonitrile with an alcohol 1 to give the nitrile 2. Akio Baba of Osaka University showed (Angew. Chem. Int. Ed. 2011, 50, 8623) that a ketene silyl acetal 4 could be condensed with a carboxylic acid 3 to give the β-keto ester 5. Timothy W. Funk of Gettysburg College found (Tetrahedron Lett. 2010, 51, 6726) that the cyclopropanol 6, readily prepared by Kulinkovich condensation of an alkene with an ester, opened with high regioselectivity to give the branched ketone 7. In an elegant application of C–H functionalization, Yong Hae Kim of KAIST and Kieseung Lee of Woosuk University added (Tetrahedron Lett. 2011, 52, 4662) the acetal 9 in a conjugate sense to 8 to give 10. Hitoshi Kuniyasu and Nobuaki Kambe of Osaka University devised (Tetrahedron Lett. 2010, 51, 6818) conditions for the Pd-catalyzed carbonylation of a silyl alkyne 11 to the ester 12 with high geometric control. Dennis G. Hall of the University of Alberta also observed (Chem. Sci. 2011, 2, 1305) good geometric control in the rearrangement of the vinyl carbinol 13 to the alcohol 14. Takashi Tomioka of the University of Mississippi condensed (J. Org. Chem. 2011, 76, 8053) the anion 16, prepared in situ from lithio acetonitrile and 1-iodobutane, with the aldehyde 15 to give a nitrile, which was carried onto the aldehyde 17, again with good control of geometry. Bruce H. Lipshutz of the University of California, Santa Barbara established (Org. Lett. 2011, 13, 3818) conditions for the Negishi coupling of an alkenyl halide 18 to give 20 with retention of alkene geometry. Daesung Lee of the University of Illinois, Chicago found (J. Am. Chem. Soc. 2011, 133, 12964) that a Pt catalyst rearranged a silyl cyclopropene 21 to the allene 22. Jan Deska of the Universität zu Köln prepared (Angew. Chem. Int. Ed. 2011, 50, 9731) the enantiomerically enriched allene 25 by lipase-mediated esterification of the prochiral 23.

C–N Ring Construction: The Waser Synthesis of Jerantinine E

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Ni Catalyst ◽  
University Of Alberta ◽  
Princeton University ◽  
In Situ Preparation ◽  
National University ◽  
The University ◽  
École Polytechnique ◽  
Pais Vasco ◽  
Multicomponent Coupling

James A. Bull of Imperial College London prepared (J. Org. Chem. 2013, 78, 6632) the aziridine 2 with high diastereocontrol by adding the anion of diiodomethane to the imine 1. Karl Anker Jørgensen of Aarhus University observed (Chem. Commun. 2013, 49, 6382) high ee in the distal aziridination of 3 to give 4. Benito Alcaide of the Universidad Complutense de Madrid and Pedro Almendros of ICOQ- CSIC Madrid reduced (Adv. Synth. Catal. 2013, 355, 2089) the β-lactam 5 to the azetidine 6. Hiroaki Sasai of Osaka University added (Org. Lett. 2013, 15, 4142) the allenoate 8 to the imine 7, delivering the azetidine 9 in high ee. Tamio Hayashi of Kyoto University, the National University of Singapore, and A*STAR devised (J. Am. Chem. Soc. 2013, 135, 10990) a Pd catalyst for the enanti­oselective addition of the areneboronic acid 11 to the pyrroline 10 to give 12. Ryan A. Brawn of Pfizer (Org. Lett. 2013, 15, 3424) reported related results. Nicolai Cramer of the Ecole Polytechnique Fédérale de Lausanne developed (J. Am. Chem. Soc. 2013, 135, 11772) a Ni catalyst for the cyclization of the formamide 13 to the lactam 14. Andrew D. Smith of the University of St. Andrews used (Org. Lett. 2013, 15, 3472) an organocatalyst to cyclize 15 to 16. Jose L. Vicario of the Universidad del Pais Vasco effected (Synthesis 2013, 45, 2669) the multicomponent coupling of 17, 18, and 19, mediated by an organocatalyst, to construct 20 in high ee. André Beauchemin of the University of Ottawa explored (J. Org. Chem. 2013, 78, 12735) the thermal cyclization of ω-alkenyl hydroxyl amines such as 21. Abigail G. Doyle of Princeton University developed (Angew. Chem. Int. Ed. 2013, 52, 9153) a Ni catalyst for the enantioselective addition of aryl zinc bromides such as 24 to the pro­chiral 23, to give 25 in high ee. Dennis G. Hall of the University of Alberta developed (Angew. Chem. Int. Ed. 2013, 52, 8069) an in situ preparation of the allyl boronate 26 in high ee. Addition to the aldehyde 27 proceeded with high diasteroselectivity.

TEM Studies of Shear Bands in a Bulk Metallic Glass Based Composite

2001 ◽  
Vol 7 (S2) ◽  
pp. 1120-1121
Author(s):  
E. Pekarskaya ◽  
C.P. Kim ◽  
W.L. Johnson
Keyword(s):  
Metallic Glasses ◽  
Shear Bands ◽  
High Yield ◽  
In Situ Tem ◽  
Two Phase ◽  
University Of Illinois ◽  
Glass Forming ◽  
The University ◽  
Very High

In 1980’s the discovery of multicomponent systems with exceptional glass forming ability enabled the synthesis of metallic glasses at relatively low cooling rates, 10−1 — 102 K/s and at a larger thicknesses. Bulk metallic glasses normally have very high yield stress, σy = 0.02 · Y (Y is Young’s modulus), high elastic limit of about 2%, but fail with very little global plasticity, typically along a localized shear band at a 45 degree angle with respect to the applied stress.The material studied in the present work is a two-phase Zr56.3Ti13.8Cu6.9Ni5.6Nb5.0Be12.5 alloy,prepared by in-situ processing. The alloy consists of amorphous and crystalline phases. In-situ TEM straining (tensile) experiments were performed at room temperature in JEOL 4000EX operating at 300kV. The experiments were carried out in the Center for Microanalysis of Materials in the University of Illinois at Urbana-Champaign. The goal of the study was to understand the deformation mechanisms of such composite material.

Carbon–Carbon Bond Construction: The Baran Synthesis of (+)-Chromazonarol

2015 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Grignard Reagent ◽  
Iron Catalyst ◽  
Alkyl Halide ◽  
Titanocene Dichloride ◽  
Secondary Amide ◽  
Reductive Coupling ◽  
Quaternary Centers ◽  
Carbon Carbon Bond ◽  
The University

Daniel J. Weix of the University of Rochester effected (Org. Lett. 2012, 14, 1476) the in situ reductive coupling of an alkyl halide 2 with an acid chloride 1 to deliver the ketone 3. André B. Charette of the Université de Montréal (not illustrated) developed (Nature Chem. 2012, 4, 228) an alternative route to ketones by the coupling of an organometallic with an in situ-activated secondary amide. Mahbub Alam and Christopher Wise of the Merck, Sharpe and Dohme UK chemical process group optimized (Org. Process Res. Dev. 2012, 16, 453) the opening of an epoxide 4 with a Grignard reagent 5. Ling Song of the Fujian Institute of Research on the Structure of Matter optimized (J. Org. Chem. 2012, 77, 4645) conditions for the 1,2-addition of a Grignard reagent (not illustrated) to a readily enolizable ketone. Wei-Wei Liao of Jilin University conceived (Org. Lett. 2012, 14, 2354) of an elegant assembly of highly functionalized quaternary centers, as illustrated by the conversion of 7 to 8. Antonio Rosales of the University of Granada and Ignacio Rodríguez-García of the University of Almería prepared (J. Org. Chem. 2012, 77, 4171) free radicals by reduction of an ozonide 9 in the presence of catalytic titanocene dichloride. In the absence of the acceptor 10, the dimer of the radical was obtained, presenting a simple alternative to the classic Kolbe coupling. Marc L. Snapper of Boston College found (Eur. J. Org. Chem. 2012, 2308) that the difficult ketone 12 could be methylenated following a modified Peterson protocol. Yoshito Kishi of Harvard University optimized (Org. Lett. 2012, 14, 86) the coupling of 15 with 16 to give 17. Masaharu Nakamura of Kyoto University devised (J. Org. Chem. 2012, 77, 1168) an iron catalyst for the coupling of 18 with 19. The specific preparation of trisubsituted alkenes is an ongoing challenge. Quanri Wang of Fudan University and Andreas Goeke of Givaudan Shanghai fragmented (Angew. Chem. Int. Ed. 2012, 51, 5647) the ketone 21 by exposure to 22 to give the macrolide 23 with high stereocontrol.

Alkene Metathesis: Synthesis of Panaxytriol (Lee), Isofagomine (Imahori and Takahata), Elatol (Stoltz), 5-F2t -Isoprostane (Snapper), and Ottelione B (Clive)

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Grignard Reagent ◽  
Conjugate Addition ◽  
Ring Closing Metathesis ◽  
University Of Illinois ◽  
Enantiomerically Pure ◽  
University Of Alberta ◽  
Cross Metathesis ◽  
Grubbs Catalysts ◽  
The University ◽  
First And Second Generation

Alkene metathesis has been used to prepare more and more challenging natural products. The first and second generation Grubbs catalysts 1 and 2 and the Hoveyda catalyst 3 are the most widely used. Daesung Lee of the University of Illinois at Chicago designed (Organic Lett. 2008, 10, 257) a clever chain-walking cross metathesis, combining 4 and 5 to make 6. The diyne 3 was carried on (3R, 9R, 10R )-Panaxytriol 7. Tatsushi Imahori and Hiroki Takahata of Tohoku Pharmaceutical University found (Tetrahedron Lett. 2008, 49, 265) that of the several derivatives investigated, the unprotected alcohol 8 cyclized most efficiently. Selective cleavage of the monosubstituted alkene followed by hydroboration delivered the alkaloid Isofagomine 10. Brian M. Stoltz of Caltech established (J. Am. Chem. Soc. 2008 , 130 , 810) the absolute configuration of the halogenated chamigrene Elatol 14 using the enantioselective enolate allylation that he had previously devised. A key feature of this synthesis was the stereocontrolled preparation of the cis bromohydrin. Marc L. Snapper of Boston College opened (J. Org. Chem. 2008, 73, 3754) the strained cyclobutene 15 with ethylene to give the diene 16. Remarkably, cross metathesis with 17 delivered 18 with high regioselectivity, setting the stage for the preparation of the 5-F2t - Isoprostane 19. Derrick L. J. Clive of the University of Alberta assembled (J. Org. Chem. 2008, 73, 3078) Ottelione B 26 from the enantiomerically-pure aldehyde 20. Conjugate addition of the Grignard reagent 21 derived from chloroprene gave the kinetic product 22, that was equilibrated to the more stable 23. Addition of vinyl Grignard followed by selective ring-closing metathesis then led to 26.

New Methods for Carbon-Carbon Bond Construction

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
Allylic Alcohol ◽  
Ni Catalyst ◽  
University Of Michigan ◽  
Carbon Carbon Bond ◽  
University Of Technology ◽  
Duke University ◽  
Michael Acceptors ◽  
Leaving Groups ◽  
The University

Mohammad Navid Soltani Rad of Shiraz University of Technology has shown (Tetrahedron Lett. 2007, 48, 6779) that with tosylimidazole (TsIm) activation in the presence of NaCN, primary, secondary and tertiary alcohols are converted into the corresponding nitriles. Gregory C. Fu of MIT has devised (J. Am. Chem. Soc. 2007, 129, 9602) a Ni catalyst that mediated the coupling of sp3-hybridized halides such as 3 with sp3-hybridized organoboranes such as 4, to give 5. Usually, carbanions with good leaving groups in the beta position do not couple efficiently, but just eliminate. Scott D. Rychnovsky of the University of California, Irvine has found (Organic Lett . 2007, 9, 4757) that initial protection of 6 as the alkoxide allowed smooth reduction of the sulfide and addition of the derived alkyl lithium to the amide 7 to give 8. Doubly-activated Michael acceptors such as 11 are often too unstable to isolate. J. S. Yadav of the Indian Institute of Chemical Technology, Hyderabad has shown (Tetrahedron Lett. 2007, 48, 7546) that Baylis-Hillman adducts such as 9 can be oxidized in situ, with concomitant Sakurai addition to give 12. Rather than use the usual Li or Na or K enolate, Don M. Coltart of Duke University has found (Organic Lett. 2007, 9, 4139) that ketones such as 13 will condense with amides such as 14 to give the diketone 15 on exposure to MgBr2. OEt2 and i -Pr2 NEt. Simultaneously, Gérard Cahiez of the Université de Cergy (Organic Lett. 2007, 9, 3253) and Janine Cossy of ESPCI Paris (Angew. Chem. Int. Ed. 2007, 46, 6521) reported that Fe salts will catalyze the coupling of sp2 -hybridized Grignard reagents such as 17 with alkyl halides. John Montgomery of the University of Michigan has described (J. Am. Chem. Soc. 2007, 129, 9568) the Ni-mediated regio- and enantioselective addition of an alkynes 20 to an aldehyde 19 to give the allylic alcohol 21. In a third example of sp2 - sp3 coupling, Troels Skrydstrup of the University of Aarhus has established (J. Org. Chem. 2007, 72, 6464) that Negishi coupling with alkenyl phosponates such as 23 proceeded efficiently.

C-N Ring Construction: The Synthesis of Decursivine by Mascal and by Jia

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Pyridinium Salt ◽  
University Of California ◽  
Reductive Coupling ◽  
University Of Arkansas ◽  
Santa Barbara ◽  
University Of Illinois ◽  
Enantiomerically Pure ◽  
Du Bois ◽  
Duke University ◽  
The University

Barry M. Trost and Justin Du Bois of Stanford University described (Org. Lett. 2011, 13, 3336) the cyclization of 1 to the activated aziridine 2. Liming Zhang of the University of California, Santa Barbara, rearranged (Angew. Chem. Int. Ed. 2011, 50, 3236) the propergylic amine 3 to the azetidinone 4 by N-H insertion of an intermediate Au carbene. Xiao Zheng and Pei-Qiang Huang of Xiamen University effected (J. Org. Chem. 2011, 76, 4952) reductive coupling of 6 with 7 to deliver the ester 8 . Eiji Tayama of Niigata University found (Tetrahedron Lett. 2011, 52, 1819) that 9 could be alkenylated with 10 with substantial retention of absolute configuration. Duncan J. Wardrop of the University of Illinois at Chicago, en route to a synthesis of (-)-swainsonine, observed (Org. Lett. 2011 , 13, 2376) high diastereocontrol in the cyclization of 12 to 13. Iain Coldham of the University of Sheffield also observed (J. Org. Chem. 2011, 76, 2360) substantial diastereoselection in the cyclization of 14 to 15. Robert E. Gawley of the University of Arkansas established (Org. Lett. 2011, 13, 394) that exposure of metalated 16 to just 5 mol % of a chiral ligand was sufficient to enable enantioselective coupling, to deliver 17. Christian Nadeau of Merck Frosst effected (J. Am. Chem. Soc. 2011, 133, 2878) enantioselective addition to the pyridinium salt 19 to give 20. Jiyong Hong of Duke University observed (Org. Lett. 2011, 13, 796) that enantiomerically pure 21 cyclized to the cis diastereomer of 22. With the Hayashi catalyst, cyclization could be driven toward the trans diastereomer, 22, enabling the synthesis of (+)-myrtine. Dawei Ma of the Shanghai Institute of Organic Chemistry found (Org. Lett. 2011, 13, 1602) that the Hayashi catalyst also directed the relative and absolute outcome in the addition of 24 to 23 , to give the piperidine 25. Donn G. Wishka of Pfizer/Groton devised (J. Org. Chem. 2011, 76, 1937) a practical route to the cis-substituted azepane 27, by Beckmann rearrangement of the enantiomerically pure 26 followed by reduction and oxidative cleavage.

C–C Bond Construction: The Hou Synthesis of (−)-Brevipolide H

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Conjugate Addition ◽  
University Of Illinois ◽  
University Of Texas ◽  
Heck Cyclization ◽  
University Of Technology ◽  
Propargylic Alcohol ◽  
Irkutsk Institute ◽  
Aqueous Conditions ◽  
The University

Yao Fu and Lei Liu of the University of Science and Technology of China devised (Chem. Eur. J. 2014, 20, 15334) conditions for the coupling of a halide 2 with a tosyl­ate 1 with inversion of absolute configuration, leading to 3. Hegui Gong of Shanghai University coupled (J. Am. Chem. Soc. 2014, 136, 17645) the glucosyl bromide 4 with an anhydride 5 to give the ketone 6. Luigi Vaccaro of the Università di Perugia showed (Org. Lett. 2014, 16, 5721) that TBAF promoted the opening of the epoxide 7 with the ketene silyl acetal 8, leading to the lactone 9. Valérie Desvergnes and Yannick Landais of the University of Bordeaux assembled (Chem. Eur. J. 2014, 20, 9336) the diketone 12 by using a Stetter catalyst to promote the conjugate addition of the acyl silane 11 to the enone 10. Thomas Werner of the Leibniz-Institute for Catalysis reported (Eur. J. Org. Chem. 2014, 6873) the enantioselective conversion of the prochiral triketone 13 to the bicyclic enone 15 by an intramolecular Wittig reaction, mediated by 14. Elizabeth H. Krenske of the University of Queensland and Christopher J. O’Brien also reported (Angew. Chem. Int. Ed. 2014, 53, 12907) progress (not illustrated) on catalytic Wittig reactions. Michael J. Krische of the University of Texas showed (J. Am. Chem. Soc. 2014, 136, 11902) that Ru-mediated addition of 17 to the aldehyde derived in situ from 16 gave 18 with high Z-selectivity. Vladimir Gevorgyan of the University of Illinois at Chicago constructed (J. Am. Chem. Soc. 2014, 136, 17926) the trisubstituted alkene 20 by the intramolecular Heck cyclization of 19. Kálmán J. Szabó of Stockholm University opti­mized (Chem. Commun. 2014, 50, 9207) the Pd-catalyzed borylation of the alkene 21 followed by in situ addition to the aldehyde 22 to give 23. Boris A. Trofimov of the Irkutsk Institute of Chemistry Siberian Branch devel­oped (Eur. J. Org. Chem. 2014, 4663) aqueous conditions for the preparation of a propargylic alcohol 26 by the addition of an alkyne 25 to the ketone 24. Huanfeng Jiang of the South China University of Technology prepared (Angew. Chem. Int. Ed. 2014, 53, 14485) the alkyne 28 by the oxidative elimination of the tosylhydrazone 27.

Five Decades of Research Experience in Speech Anatomy and Physiology

2016 ◽  
Vol 1 (5) ◽  
pp. 4-12
Author(s):  
David P. Kuehn
Keyword(s):  
Ohio State University ◽  
State University ◽  
Research Experience ◽  
University Of Iowa ◽  
University Of Illinois ◽  
Anatomy And Physiology ◽  
The Ohio State University ◽  
Speech Science ◽  
The University ◽  
East Carolina University

This report highlights some of the major developments in the area of speech anatomy and physiology drawing from the author's own research experience during his years at the University of Iowa and the University of Illinois. He has benefited greatly from mentors including Professors James Curtis, Kenneth Moll, and Hughlett Morris at the University of Iowa and Professor Paul Lauterbur at the University of Illinois. Many colleagues have contributed to the author's work, especially Professors Jerald Moon at the University of Iowa, Bradley Sutton at the University of Illinois, Jamie Perry at East Carolina University, and Youkyung Bae at the Ohio State University. The strength of these researchers and their students bodes well for future advances in knowledge in this important area of speech science.

University Geographies and Folk Music Landscapes

2016 ◽  
Vol 33 (1) ◽  
pp. 92-116 ◽  
Author(s):  
David K. Blake
Keyword(s):  
Mass Culture ◽  
Folk Music ◽  
Traditional Music ◽  
Rural Landscape ◽  
Power Structures ◽  
Distant Object ◽  
University Of Illinois ◽  
Liberal Politics ◽  
Cultural Form ◽  
The University

By examining folk music activities connecting students and local musicians during the early 1960s at the University of Illinois at Urbana-Champaign, this article demonstrates how university geographies and musical landscapes influence musical activities in college towns. The geography of the University of Illinois, a rural Midwestern location with a mostly urban, middle-class student population, created an unusual combination of privileged students in a primarily working-class area. This combination of geography and landscape framed interactions between students and local musicians in Urbana-Champaign, stimulating and complicating the traversal of sociocultural differences through traditional music. Members of the University of Illinois Campus Folksong Club considered traditional music as a high cultural form distinct from mass-culture artists, aligning their interests with then-dominant scholarly approaches in folklore and film studies departments. Yet students also interrogated the impropriety of folksong presentation on campus, and community folksingers projected their own discomfort with students’ liberal politics. In hosting concerts by rural musicians such as Frank Proffitt and producing a record of local Urbana-Champaign folksingers called Green Fields of Illinois (1963), the folksong club attempted to suture these differences by highlighting the aesthetic, domestic, historical, and educational aspects of local folk music, while avoiding contemporary socioeconomic, commercial, and political concerns. This depoliticized conception of folk music bridged students and local folksingers, but also represented local music via a nineteenth-century rural landscape that converted contemporaneous lived practice into a temporally distant object of aesthetic study. Students’ study of folk music thus reinforced the power structures of university culture—but engaging local folksinging as an educational subject remained for them the most ethical solution for questioning, and potentially traversing, larger problems of inequality and difference.

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