Palladium Porphyrin Catalyzed Hydrogenation of Alkynes: Stereoselective Synthesis of cis-Alkenes
摘要:
(Tetraphenylporphyrin)palladium was developed as a catalyst for the chemoselective and stereoselective hydrogenation of alkynes to cis-alkenes by the syn-addition of hydrogen. Alkynes containing various functional groups were tolerated in the reaction, which gave the corresponding cis-alkenes in good to excellent yields.
The scope of the Giese reaction is expanded using readily available alkyl tosylates as substrates and nucleophilic cobalt(I) catalysts under visible-light irradiation. The reaction proceeds preferentially with less bulky primary alkyl tosylates. This unique reactivity enables the regio-selective Giese reaction of polyol derivatives.
在可见光照射下,使用容易获得的甲苯磺酸烷基酯作为底物和亲核钴 ( I ) 催化剂,扩大了 Giese 反应的范围。该反应优先使用体积较小的伯烷基甲苯磺酸酯进行。这种独特的反应性使多元醇衍生物的区域选择性吉斯反应成为可能。
Intramolecular Kulinkovich–de Meijere reactions of various disubstituted alkenes bearing amide groups
作者:Claire Madelaine、Nouara Ouhamou、Angèle Chiaroni、Emeline Vedrenne、Laurence Grimaud、Yvan Six
DOI:10.1016/j.tet.2008.06.067
日期:2008.9
A range of amides fitted with (E) or (Z) disubstituted alkene groups were prepared and evaluated in intramolecular Kulinkovich-de Meijere reactions. The corresponding aminocyclopropanes were obtained with high diastereoselectivity. Good yields could be achieved with substrates bearing suitable substitutions at the olefin moieties. (C) 2008 Elsevier Ltd. All rights reserved.