NEW SI-C BOND-FORMING REACTIONS OVER SOLID-BASE CATALYSTS

The reactions of silanes with carbanions generated on the surface of s olid bases bring about the nucleophilic substitution at the Si atom to form Si-C bonds. The reaction of alkynes with silanes afforded alkyny lsilanes. For example, the reaction of tert-BuC equivalent to CH or n- BuC equivalent to CH with Et2SiH2 in the presence of KNH2/Al2O3 gave t ert-BuC-CSiEt2H and n-BuC equivalent to CSiEt2H in a 77% and 67% yield , respectively, at 329 K. Toluene also reacted with Et2SiH2 at 329 K t o yield benzyldiethylsilane in a 85% yield. The reactions of l-alkynes with Me3SiC equivalent to CH in the presence of KNH2/Al2O3 or KF/Al2O 3 resulted in a novel type of metathesis reaction between the two alky nes. For example, the reaction of PhC equivalent to CH with Me3SiC equ ivalent to CH afforded PhC equivalent to CSiMe3 and HC-CH in a high yi eld. These new types of base-catalyzed reactions provide new synthetic routes for Si-C bond formation. (C) 1998 Elsevier Science B.V. All ri ghts reserved.