ChemInform Abstract: Silyl Effect on the Regioselective Synthesis of Silylated Alkylidenecyclopropanes.

Abstract

2000organo-silicon compounds, isocyclic C derivatives organo-silicon compounds, isocyclic C derivatives S 0064 -184Silyl Effect on the Regioselective Synthesis of Silylated Alkylidenecyclopropanes.-Nucleophilic substitution of silylated cyclopropanes of type (I) is found to occur on the carbon bearing the silyl group. However, the reaction of analogues in which the silyl group is located on the ring with hard nucleophiles takes place on the ring, whereas with soft nucleophiles the vinyl group is attacked. Starting from disilylated derivatives like (X) no ring attack is observed, indicating that the effect of the vinyl silyl group dominates. Electrophilic substitution of silanes of type (XII) by Ph-CHO occurs regioselectively on the cyclopropane ring.