Reaction of the N-(α-chloroalkyloxycarbonyl)pyrrolidines 1 with lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 2.5 mol-%) in the presence of different electrophiles [iBuCHO, tBuCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe, Ph2CO, Me3SiCl], in THF at temperatures ranging between –78 and –60°C leads, after hydrolysis with water, to the expected functionalized carbamates 2. Deprotection
Probing Competitive Enantioselective Approach Vectors Operating in the Jacobsen−Katsuki Epoxidation: A Kinetic Study of Methyl-Substituted Styrenes
作者:Peter Fristrup、Brian B. Dideriksen、David Tanner、Per-Ola Norrby
DOI:10.1021/ja051851f
日期:2005.10.1
kinetic data for the reactivity of the seven possible methyl-substituted styrenes (mono-, di- and trisubstituted) relative to styrene itself, ee values were measured by chiral GC, and absoluteconfigurations were secured by chemical correlation. Of particular interest was the switch in absoluteconfiguration at the benzylic position of the epoxides derived from (Z)- and (E)-alpha,beta-dimethylstyrene,