organocatalyst to catalyze the asymmetric domino Michael–alkylation reaction between cyclohexane‐1,3‐dione derivatives and bromonitrostyrenes. For dimedone, the corresponding bicyclic 2,3‐dihydrofurans with two stereocenters were obtained in up to 99 % yield with 95:5 d.r. and 96 % ee. For prochiral 5‐monosubstituted cyclohexane‐1,3‐diones, the desymmetrization reaction provided the bicyclic 2,3‐dihydrofurans
Neber; Burgard; Thier, Justus Liebigs Annalen der Chemie, 1936, vol. 526, p. 277,287
作者:Neber、Burgard、Thier
DOI:——
日期:——
Stereospecific approach to α,β-disubstituted nitroalkenes via coupling of α-bromonitroalkenes with boronic acids and terminal acetylenes
作者:Madhu Ganesh、Irishi N.N. Namboothiri
DOI:10.1016/j.tet.2007.09.012
日期:2007.11
(Z)-alpha-Bromo-beta-substituted nitroethylenes undergo facile Suzuki coupling with aryl, heteroaryl, and vinylboronic acids in the presence of Pd(PPh3)(4) as catalyst to afford (E)-alpha,beta-disubstituted nitroethylenes in high yield (up to 95%) and complete specificity. Similar coupling of alpha-bromonitroethylenes with terminal acetylenes (Sonogashira coupling) provides a novel route to (E)-nitroenynes. These Pd-catalyzed coupling methods offer a convenient and stereospecific entry into a diverse array of synthetically and biologically useful alpha,beta-disubstituted nitroethylenes. (c) 2007 Elsevier Ltd. All rights reserved.
Rosenmund; Kuhnhenn, Chemische Berichte, 1923, vol. 56, p. 1265