Selective Functionalization of a Variety of Hydrocarbon C(sp3)–H Bonds Initiated by Cp*W(NO)(CH2CMe3)(η3-CH2CHCHPh)

Abstract

Cp*W(NO)(CH2CMe3)(η3-CH2CHCHPh) (1) effects C(sp3)–H activations of methane, ethane, propane, and n-butane exclusively at their terminal carbons and forms the corresponding Cp*W(NO)(alkyl)(η3-CH2CHCHPh) complexes. It also activates (n-Bu)2O, 1-chloropropane, and Me4Si in a similar manner. Exposure of the Cp*W(NO)(alkyl)(η3-CH2CHCHPh) complexes to carbon monoxide results in initial 1,1-CO insertion into the newly formed tungsten–alkyl bonds and formation of the corresponding η1-acyl complexes, some of which can be isolated. Additional functionalization of the C–H activation products occurs upon exposure to CO under more forcing conditions. Such treatment produces η2-bound unsaturated-ketone complexes resulting from CO insertion into the W–alkyl σ bonds followed by cross-coupling of the η1-acyl and the η3-allyl ligands and coordination of CO at the resulting vacant coordination site at tungsten. The unsaturated ketones can be released from the metal’s coordination spheres either by photolysis of the complex...