Mechanisms of Hydride Abstraction from Organometallic Compounds. Effects of Two β-Metal Substituents on the Kinetics of Dehydrometalation

Article abstract of DOI:10.1021/jo00331a013

A series of 1,3-dimetallopropanes, Me3M(CH2)3M'Me3, in which M and M' are C, Si, Ge, Sn, and Pb, has been reacted with triphenylcarbenium ion to remove hydride and yield triphenylmethane.The rate constants for these reactions follow the Hammett-type relationship log k₂ = ρΣ?⁺ + constant, where Σ?⁺ is the sum of ?⁺_CH2MPh3 for both metal groups.This relationship leads to the conclusion that both metal groups simultaneously stabilize a carbocation intermediate by vertical stabilization through ?-? conjugation.