Chiral Synthesis via Organoboranes. 11. Hydroboration. 82. Asymmetric Hydroboration of 1-Heteroarylcycloalkenes with Monoisopinocampheylborane. Synthesis of<i>trans</i>-2-Heteroarylcycloalkyl Boronates and Derived Alcohols of Very High Enantiomeric Purity
作者:Herbert C. Brown、Ashok K. Gupta、J. V. N. Vara Prasad
DOI:10.1246/bcsj.61.93
日期:1988.1
The hydroboration of representative 1-heteroarylcycloalkenes with monoisopinocampheylborane (IpcBH2) was investigated systematically to establish the degree of asymmetric induction during hydroboration. The hydroboration of 1-heteroarylcyclopentene with IpcBH2 at −25 °C proceeded cleanly to afford the corresponding dialkylboranes. These dialkylboranes, upon treatment with acetaldehyde and then oxidation
系统地研究了代表性 1-杂芳基环烯烃与单异松蒎基硼烷 (IpcBH2) 的硼氢化反应,以确定硼氢化反应过程中的不对称诱导程度。1-杂芳基环戊烯与 IpcBH2 在 -25 °C 下的硼氢化反应顺利进行,得到相应的二烷基硼烷。这些二烷基硼烷用乙醛处理然后氧化,得到相应的 85-86% ee 的反式-2-杂芳基环烷醇。类似地,1-杂芳基环己烯在用 IpcBH2 进行硼氢化反应后,再进行乙醛处理和氧化,得到相应的醇(约 10 毫升)。90% EE。衍生自 1-杂芳基环戊烯和 IpcBH2 的二烷基硼烷或烷基硼酸可以重结晶以提供接近 100% ee 的材料。从这样的二烷基硼烷或烷基硼酸,相应的硼酸盐约。制备并分离了 100% ee。这些被证明是用于有机合成的高度通用的合成中间体。
Nickel-catalysed electrochemical coupling of 2- and 3-bromothiophene with alkyl and alkenyl halides
2- or 3-bromothiophene are efficiently coupled with activated alkyl chlorides (alpha-chloroesters, alpha-chloroketones, alpha-chloronitriles), benzyl chloride or vinyl halides, in a one step electrochemical reaction, using the sacrificial anode process and catalysis by NiBr2-2,2'-bipyridine (bipy). (C) 1997 Elsevier Science Ltd.
Mass spectra of some 2- and 3-cycloalkenylfurans and -cycloalkenylthiophenes and their oxyderivatives
作者:Arlene P. Rothwell、Karl V. Wood、Ashok K. Gupta、J. V. N. Vara Prasad
DOI:10.1002/oms.1210221206
日期:1987.12
BROWN, HERBERT C.;GUPTA, ASHOK K.;PRASAD, J. V. N. VARA, BULL. CHEM. SOC. JAP., 61,(1988) N 1, 93-100
作者:BROWN, HERBERT C.、GUPTA, ASHOK K.、PRASAD, J. V. N. VARA
DOI:——
日期:——
[EN] NOVEL PHOTOCHROMIC POLYMERS AND METHODS OF SYNTHESIZING SAME<br/>[FR] NOUVEAUX POLYMERES PHOTOCHROMES ET PROCEDES POUR SYNTHETISER CES DERNIERS
申请人:UNIV FRASER SIMON
公开号:WO2002006361A2
公开(公告)日:2002-01-24
Ring-opening metathesis polymerization (ROMP) of a photochromic 1,2-bis-(3-thienyl)-cyclopentene monomer generated a series of novel polymers. All polymers exhibit reversible light-activated interconversion between their colorless-open and their colored-closed forms.