(η3-α-Silabenzyl)tungsten complexes: An isolable intermediate for interconversion between a silylene complex and a silyl complex through 1,2-aryl migration

摘要

η~3-α-Silabenzyl complexes Cp W(CO)_2{η ~3(Si,C,C)-Si(p-Tol)_2R} (1a, R = Me; 1b, R = p-Tol; Cp~* = η~5-C_5Me_5, p-Tol = p-tolyl), the first silicon analogues of η~3-benzyl complexes, were synthesized by abstraction of DMAP (4-(dimethylamino)pyridine) with BPh3 either from (aryl)(DMAP·silylene)tungsten complexes 2a,b at room temperature or from (arylsilyl)(DMAP)tungsten complexes 3a,b under irradiation. Complex 1 was demonstrated to be a key intermediate for the interconversion between 2 and 3 and to serve as a synthetic equivalent for both base-free silylene complexes and coordinatively unsaturated silyl complexes.