Laboratoire de Chimie des Organominéraux, Université Paul Sabatier, Toulouse France
Abstract:
Ketenes add to germyl- and silylphosphines R3MPEt2 with opening of the carbonyl group and formation of phosphorylated alkenoxygermanes or -silanes (R′H, Ph). These adducts are thermally stable and only the addition derivative of diphenylketene and Me3SiPEt2 exhibits metallotropic isomerization to a C-derivative after prolonged heating. Hydrolysis of these addition compounds is a new approach to the acylphosphines R2CH-CO-PEt2. Diketene also reacts with germyl- and silylphosphines with acyloxygen bond cleavage and formation of metallated and phosphorylated ketoenolates of the type . These derivatives isomerize either partially (MSi) or completely (MGe) into R3MOC(CH3)CHCOPEt2. Their hydrolysis constitutes a new method of synthesis of the phosphorylated β-diketone . The ketoenolates from the addition reaction of the hydrosilylphosphine, Me2Si(H)PEt2, cyclize readily after partial isomerization by the intramolecular addition SiH to CO, to give phosphorylated siladioxane and siladioxene. The conformation of these heterocyclic compounds has been studied.