Carbon–hydrogen activation in a 1,3-diene coordinated onto a molybdenum(II) centre

Abstract

Trimethyl phosphite reacts selectively with [Br[graphic omitted]HMe(η²-MeC₂Me)(η⁵-C₅H₅)][BF₄] to form the X-ray crystallographically identified η⁴(5e)-butadienyl cation [BrMoC(Me)-η³-{C(Me)C(Me)CHMe}{P(OMe)₃}(η⁵-C₅H₅)][BF₄], which in turn reacts with Bu^s₂AIH to form the 1,3-diene complex [BrMo{η⁴CH(Me)C(Me)C(Me)C(H)Me}{P(OMe)₃}(η⁵-C₅H₅)]; this unexpectedly reacts regioselectively with [Ph₃C][BF₄] to regenerate the parent η⁴(5e)-butadienyl cation with significant implications for alkenic C–H activation.