The Reactions of Carbon Monoxide with Silyl and Silenyl Lithium – Synthesis and Isolation of the First Stable Tetra‐Silyl Di‐Ketyl Biradical and 1‐Silaallenolate Lithium

Abstract

Reactions of carbon monoxide (CO) with tBu 2 MeSiLi and (E)-(tBu 2 MeSi)(tBuMe 2 Si)C = Si-(SiMetBu 2 )Li·2 THF (4)w ere studied both experimentally and computationally.R eaction of tBu 2 MeSiLi with CO in hexane yields the first stable tetra-silyl di-ketyl biradical [(tBu 2 MeSi) 2 COLi]C 2 (3). Reaction of 4 with CO yields selectively and quantitatively the first reported 1-silaallenolate, (tBu 2 MeSi)(tBuMe 2 Si)C = C = Si(SiMetBu 2 )OLi·THF (5). Both 3 and 5 were characterized by X-rayc rystallography and biradical 3 also by EPR spectroscopy. Silaallenolate 5 reacts with Me 3 SiCl to produce siloxy substituted 1-silaallene (tBu 2 MeSi)(tBuMe 2 Si)C=C=Si(SiMetBu 2 )OSiMe 3 .T he reaction of 4 with CO provides an ew route to 1-silaallenes.T he mechanisms of the reactions of tBuMe 2 SiLi and of 4 with CO were studied by DFT calculations. Angewandte ChemieCommunications