Synthesis and characterization of tricarbastannatranes and their reactivity in B(C6F5)3-promoted conjugate additions

Abstract

The synthesis and characterization of a series of tricarbastannatranes, in the solid state and in solution, are described. The structures of the complexes [N(CH2 CH2 CH2 )3 Sn](BF4 ), [N(CH2 CH2 CH2 )3 Sn](SbF6 ), [N(CH2 CH2 CH2 )3 Sn]4 [(SbF6 )3 Cl], and [(N(CH2 CH2 CH2 )3 Sn)2 OH][MeB(C6 F5 )3 ] were determined by X-ray crystallography. Furthermore, the B(C6 F5 )3 -promoted conjugate addition of alkyl-tricarbastannatranes to benzylidene derivatives of Meldrum's acid was investigated, and detailed mechanistic studies are presented.

Keywords: Lewis acid; Michael addition; boron; reaction mechanisms; tin.