3-methylenetetrahydrofurans and 3-methylenepyrrolidines by addition of 2-(bromozincmethyl)-2-alkenyl ethers or 2-(chloromagnesiomethyl)-2-alkenyl ethers to aldehydes, ketones and imines followed by pd(0)-catalyzed cyclization
作者:Jaap van der Louw、Juul L. van der Baan、Henk Stichter、Gerardus J.J. Out、Franciscus J.J. de Kanter、Friedrich Bickelhaupt、Gerhard W. Klumpp
DOI:10.1016/s0040-4020(01)92280-x
日期:1992.11
Reaction of 2-(bromozincmethyl)-2-alkenyl ethers 1 or 2-(chloromagnesiomethyl)-2-alkenyl ethers 2 with aldehydes, ketones and imines affords the addition products 4 and 8, which undergo Pd(0)-catalyzed cyclization to the 3-methylenetetrahydrofurans 6 (R1 = H) and 3-methylenepyrrolidines 10 (R1 = H). Addition of 1a or 1b to α,β-unsaturated substrates proceeds in the 1,2-mode only. Reaction of the 3-alkyl