Conjugate reduction of aryl acrylates with tributyltin hydride in the presence of magnesium bromide diethyl etherate
作者:Satomi Hirasawa、Hajime Nagano、Yoko Kameda
DOI:10.1016/j.tetlet.2004.01.028
日期:2004.3
The conjugate reduction of aryl acrylates performed with tributyltinhydride in the presence of magnesium bromide diethyl etherate in dichloromethane gave the corresponding saturated esters in moderate to high yields. The reduction of α-methylene-γ-benzyloxycarboxylic acid esters proceeded syn-selectively, but α-methylene-β-oxycarboxylic acid esters afforded reductive elimination products under the
A carboxamide can be produced in a high yield by a method for producing a carboxamide, for example, represented by formula (4) :
(wherein R1 and R3 are as defined below), the method comprising a step of allowing a carboxylic acid ester represented by formula (1):
(wherein R1 represents an optionally substituented C1-C20 hydrocarbon group or an optionally substituented C3-C20 heterocyclic group, and R2 represents an optionally substituented C1-C20 hydrocarbon group), an amine represented by formula (2):
R3-NH2 (2)
(wherein R3 represents a hydrogen atom or an optionally substituented C1-C20 hydrocarbon group),
and a formamide compound represented by formula (3):
(wherein R3 is as defined above)
to react in the presence of a metal alkoxide.
We report herein that the conjugate reduction of α,β-unsaturated esters and amides, such as aryl acrylates, pantolactone esters of acrylic acids, diethyl itaconate and N-crotonylcamphorsultam, with tributyltinhydride proceeded in moderate to high yields in the presence of magnesium bromide diethyl etherate. The effect of metal halide enhancing the yields is also described.