TRIARYLPHOSPHINES, AND (CO)4FESI(CH3)2CH2CH2SI(CH3)2 A NEW ROUTE TO METAL ALKYLIDENE COMPLEXES - SYNTHESIS OF YLIDE ADDUCTS (CO)4FE-CH(R)P+AR3 FROM ALDEHYDES

Chelated disilane complex [formula omitted] (1) is treated with a variety of aromatic and aliphatic aldehydes (RCHO). Disiloxane [formula omitted] (2), iron carbonyls, and, in the case of benzaldehyde, trons-stilbene are formed. When these reactions are conducted in the presence of P(C6H5)3 or P(p-C6H4CH3)3, ylide complexes (CO)4Fe-CH(R)P+Ar3 are isolated in high yields. The displacement of P(C6H5)3 from (CO)4Fe-CH(p-C6H4OCH3)P+(C6H5)3 (4) by P(CH3)3 is shown to proceed via a dissociative mechanism. All of these reactions are interpreted as proceeding via reactive alkylidene intermediates (CO)4Fe=CHR. Protonation of (CO)4Fe-CH(C6H5)P+(C6H6)3 (3) with CF3SO3H affords C6H5CH2P+(C6H5)3 CF3SO3-. The spectral properties, relative stabilities, and mechanism of formation of the ylide complexes are discussed. It is proposed that the formation of disiloxane 2 constitutes a powerful driving force for the generation of (CO)4Fe=XLn species from 1 and O=XLn precursors. 1983, American Chemical Society. All rights reserved.

A NEW ROUTE TO METAL ALKYLIDENE COMPLEXES - SYNTHESIS OF YLIDE ADDUCTS (CO)4FE-CH(R)P+AR3 FROM ALDEHYDES, TRIARYLPHOSPHINES, AND (CO)4FESI(CH3)2CH2CH2SI(CH3)2 Academic Article