Direct Conversion of a Si-C(aryl) Bond to Si-Heteroatom Bonds in the Reactions of η³-α-Silabenzyl Molybdenum and Tungsten Complexes with 2-Substituted Pyridines

η³-α-Silabenzyl complexes Cp∗M(CO)₂-{η³(Si,C,C)-Si(p-Tol)₃} (M = Mo (1-Mo), W (1-W)) reacted with 2-substituted pyridines NC₅H₄(2-EH_n) (E = O, S (n = 1); N (n = 2)) under mild conditions to give M-Si-E-C-N (E = O, N), W-Si-N-C-S, and M-E-C-N (E = S, N) metallacycles depending on the metal M or heteroatom E. These three kinds of metallacycles were characterized by spectroscopy, elemental analysis, and X-ray crystallography. The first two silametallacycles take on some silylene complex character and are considered to form via (aryl)silylene complex intermediates generated by cleavage of the Si-C(aryl) bond in the η³-α-silabenzyl ligand of 1-Mo and 1-W. (Chemical Equation Presented).