An unexpected product of the reactions of fluorenylchlorosilanes with phosphorus ylides

Abstract

The reaction of Me₃PCh₂ with R¹R²Si(C₁₃H₉) Cl(C₁₃H₉= fluoren-9-yl), irrespective of the molar ratio of reagents, yields betaines of the Me₃P⁺CH₂SiR²R²(C₁₃H₈^–) type, whereas under similar conditions the reaction of bis(trimethylsilylmethyl)fluoren-9-ylchlorosilane with Ph₃PCMe₂ gives a stable organosilicon carbanion (X-ray analysis); the compounds were characterized by ¹³C, ²⁹Si, and ³¹P n.m.r., and u.v. spectroscopy.