AlCl3–NaI(NaBr)–t-BuOH: mild, chemo- and stereoselective reagents for hydrohalogenation of propiolic derivatives
摘要:
(Z)-beta-lodo-propenamides and -beta-iodo-propenoic esters were selectively prepared in high yields, at room temperature, through reaction of 2-propynamides and 2-propynoic esters, respectively, with AlCl3 and Nal in the presence of t-BuOH in dichloromethane. These experimental conditions are compatible with the presence of acid sensitive acetal groups. Alternative use of EtOH or H2O in place of t-BuOH was investigated. (Z)-Bromo-propenamides and corresponding esters were prepared according to a similar procedure using sodium bromide in refluxing acetonitrile. (C) 2009 Published by Elsevier Ltd.
A novel regio- and stereospecific hydrohalogenation reaction of 2-propynoic acid and its derivatives
作者:Shengming Ma、Xiyan Lu、Zhigang Li
DOI:10.1021/jo00028a055
日期:1992.1
2-Propynoic acid and its derivatives are hydrohalogenated regio- and stereospecifically by reaction with lithium halides in acetic acid, or preferably with 1 equiv of acetic acid in refluxing CH3CN, to afford the thermodynamically unfavorable (Z)-3-halopropenoic acids and their derivatives as sole products. A rationale for the regio- and stereospecificity is briefly discussed.
Differentiation of the reactivities of carbon-carbon multiple bonds in one molecule. Highly chemo- and stereo-selective hydrohalogenation of allyl or propargyl propiolates
作者:Shengming Ma、Xiyan Lu
DOI:10.1016/s0040-4039(00)97323-4
日期:1990.1
The reaction of allyl or propargyl propiolates with lithium halides in acetic acid afforded allyl or propargyl (Z)-3-halopropenoates highly chemo- and stereo-selectively by differentiation of reactivities of carbon-carbon multiple bonds in the same molecule.
MA, SHENGMING;LU, XIYAN, TETRAHEDRON LETT., 31,(1990) N2, C. 7653-7656