DBP ylides: Wittig reagents for synthesis of E-alkenes from aldehydes
作者:E. Vedejs、C. Marth
DOI:10.1016/s0040-4039(00)96322-6
日期:——
Phosphorus ylides based on the dibenzophosphole (DBP) ring system convert aldehydes into trans-disubstituted oxaphosphetanes with good to excellent selectivity. Decomposition at 70–110° affords alkenes with E:Z ratios from 6:1 to > 100:1.
A catalytic enantioselective β-O-elimination is reported. The reaction design utilizes the symmetry of meso-ketene acetal substrates and proceeds in the presence of a chiral zirconocene catalyst. Furthermore, a regiodivergent β-O-elimination, the application in diol and amino alcohol synthesis, and a DFT-supported stereochemical analysis are presented.
A Modular Olefination of Aldehydes with Thiols as Coupling Partners
作者:Sabine Bognar、Manuel van Gemmeren
DOI:10.1002/chem.202203512
日期:2023.3
A simple and modular protocol for the olefination of aldehydes with thiols as reaction partners is reported. Olefins with both aromatic and aliphatic substituents were synthesized in high yields and good selectivity via unsymmetric bissulfone intermediates. The E/Z-selectivity could be switched under kinetic control through the choice of solvent. The use of simple, transition metal-free reaction conditions
Simple protocol for enhanced (E)-selectivity in Julia–Kocienski reaction
作者:Jiří Pospíšil
DOI:10.1016/j.tetlet.2011.02.086
日期:2011.5
A short and efficient Julia-Kocienski olefination protocol, based upon the use of chelating agents (18-crown-6 or TDA-1 for K(+); 12-crown-4 or HMPA for Li(+)), was developed. This protocol enhances the (E)selectivity of the reaction and the desired olefins are obtained generally with >10:1 (E/Z)-selectivity. (C) 2011 Elsevier Ltd. All rights reserved.
VEDEJS, E.;MARTH, C., TETRAHEDRON LETT., 28,(1987) N 30, 3445-3448