Takako Muraoka, A. Matsuda, K. Itoh
Jul 20, 2002
Citations
0
Influential Citations
25
Citations
Journal
Organometallics
Abstract
The reaction of 1,6-heptadiyne derivatives with a hydrosilane in the presence of a catalytic amount of RhCl(PPh3)3 (3a) affords 1,2-dialkylidenecyclopentane derivatives (4) in moderate yields. This skeleton is constructed by the insertion of two alkyne moieties involved in the same molecule into the Rh−Si bond and the Rh−vinyl bond, consecutively. The key intermediate in this process is Rh(H)(SiR3)(Cl)(PPh3)2 (8), the formation of which is observed in a solution of CDCl3 by 1H NMR analysis. 1,6-Heptadiynes react smoothly with hydrosilanes to give 4 at room temperature in the presence of an equimolar amount of 8. The quantity of 8 can be reduced to 3 mol % of the starting diynes to complete the identical reaction at 80 °C. Rh4(CO)12 (3b) or a cationic rhodium complex [Rh(cod)(dppb)]PF6 (3c) is also effective as a catalyst precursor for the present transformation, although the selectivity of 4 is rather low. The stereochemistry of the silylvinylidene moiety of 4 has the E-configuration in the reaction catal...