Efficient synthesis of 4-ethenylidene-2-oxazolidinones via palladium-catalyzed aminocyclization of 2-butyn-1,4-diol biscarbamates
作者:Masanari Kimura、Yoshinori Wakamiya、Yoshikazu Horino、Yoshinao Tamaru
DOI:10.1016/s0040-4039(97)00790-9
日期:1997.6
4-Ethenylidene-2-oxazolidinones 2, 6, and 9 are prepared in reasonable yields by the reaction of 2-butyn-1,4-diol biscarbamates in the presence of catalytic amounts of Pd-2(dba)(3) . CHCl3 (0.005 equiv) ad triethylamine (0.1 equiv). The allenic three carbons are not aligned straight, but considerably distorted (173.6 degrees); the enamine double bond is reactive toward unsaturated amides (providng 4) and methyl vinyl ketone (providing 10). (C) 1997 Elsevier Science Ltd.