Synthesis and X-ray crystal structure of a cationic gold (I) π-(1,3-diene) complex generated via isomerization of a gold π-allene complex

The cationic gold tetramethylallene complex {[P(t-Bu)2o-biphenyl]Au(η2-Me2Cdouble bond; length as m-dashCdouble bond; length as m-dashCMe2)}+ SbF6− (1) underwent formal 1,3-hydrogen migration in CD2Cl2 solution at or below room temperature in the absence of base to form the 1,3-diene complex {[P(t-Bu)2o-biphenyl]Au[η2-H2C(Me) = C(H)–C(H)double bond; length as m-dashCMe2]}+ SbF6− (2), which was isolated in 92% yield and analyzed by X-ray crystallography.