Stereoselective synthesis of polyfunctional di- and trisubstituted cyclopentane derivatives using a new palladium catalyzed cyclization.
作者:Heinz Stadtmüller、Charles E. Tucker、Andrea Vaupel、Paul Knochel
DOI:10.1016/s0040-4039(00)61508-3
日期:1993.12
undergo a radical ring closure to give cyclopentylmethylzinc iodides when treated with Et2Zn in the presence of PdCl2(dppf) (2 mol %). In the case of 4-substituted 5-hexenyl iodides trans-cyclopentanes are obtained (> 99 : 1) whereas 1-substituted-5-hexenyl iodides provide cis-cyclopentanes (ca. 80 : 20). The presence of a substituent at both positions considerably improves the cis stereoselectivity up to