P(RNCH2CH2)3N: an efficient promoter for the direct synthesis of E-α,β-unsaturated esters
作者:Philip Kisanga、Bosco D'Sa、John Verkade
DOI:10.1016/s0040-4020(01)00782-7
日期:2001.9
Upon reacting ethyl acetate or methyl propionate with a variety of aromatic aldehydes in the presence of 1.06–1.2 equiv. of the pro-azaphosphatranes, P(MeNCH2CH2)3N, P(i-PrNCH2CH2)3N or [P(i-PrNCH2CH2)2(NHCH2CH2)N at 40–50°C for 2–6 h in isobutyronitrile, the corresponding α,β-unsaturated esters were formed as the only products. Ethyl acetate reacts with aldehydes to form exclusively E-isomers while
使乙酸乙酯或丙酸甲酯与各种芳香醛在1.06–1.2当量的条件下反应。氮杂磷杂环戊烷,P(MeNCH 2 CH 2)3 N,P(i -PrNCH 2 CH 2)3 N或[P(i- PrNCH 2 CH 2)2(NHCH 2 CH 2)N在40–50时在异丁腈中,在°C下放置2-6小时,形成了相应的α,β-不饱和酯。乙酸乙酯与醛反应仅形成E-异构体,而较高的同系物丙酸甲酯生成E的混合物和ž前者为主要产品的异构体。当用作溶剂时,丙酸甲酯选择性地形成E -α,β-不饱和酯。该反应对于制备α,β-不饱和酮不那么成功。