C–H Activation Reactions of a Nucleophilic Palladium Carbene

Abstract

The reactivity of a nucleophilic palladium carbene, [PC(sp2)P]Pd(PMe3) (1; [PC(sp2)P] = bis[2-(diisopropylphosphino)phenyl]methylene), toward the C–H bonds of CH3COCH3, CH3CN, Ph–CCH, fluorene, and 9,10-dihydroanthracene was investigated. All surveyed substrates reacted with 1. However, there was no detectable reaction of 1 with Ph2CH2. It is proposed that the pKa values of the studied C–H bonds govern their reactivity toward 1: our results show that substrates with a pKa higher than 29, such as Ph2CH2 (pKa = 32.2), do not react even with prolonged heating.