Réactions D'Hétérocycles Oxygénés avec les Trialcoylsilyl‐, ‐Germyl‐ et ‐Stannyl‐Phosphines: II. Cas des lactones et des anhydrides d'acide

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Abstract
The trialkyl‐silyl‐, ‐germyl‐ and ‐stannyl‐phosphines R3MPEt2 react with β‐propiolactone via the cleavage of the alkyl‐oxygen bond of the lactone, leading to the trialkylmetal β‐diethylphosphinopropionates R3MOCOCH2CH2PEt2 (M = Si, Ge, Sn). These reactions are accompanied by a strong polymerization of the β‐propiolactone.The germyl‐ and silyl‐phosphines cleave γ‐butyrolactone at a rather high temperature and in the presence of catalyst (ZnCl2). Only the acyl‐oxygen scission is observed in this case, with formation of the phosphorated kétoalkoxymetal derivatives R3MO(CH2)3COPEt2. Under the same conditions, the stannylphosphines decompose before reacting.In the case of the hydrosilylphosphines R2(H)SiPEt2, the kétoalkoxymetal derivative cyclises by intramolecular addition SiH/C=O with formation of 2‐sila‐1,3‐dioxepane with a phosphorated substituent: magnified image The same acyl‐oxygen cleavage is observed in the action of the metal‐IVb phosphines on succinic anhydride to lead to the kétoesters R3MOCO (CH2)2COPEt2 (M = Si, Ge, Sn). The action of the hydro‐germyl‐ or ‐silyl‐phosphines R2(H)MPEt2 leads, in a first phase, to the corresponding γ‐kétoesters R2(H)MOCOCH2CH2COPEt2 which cyclise via intramolecular addition with formation of cyclic germa‐ or sila‐alkoxy esters. magnified image