Reactions selectives des organonagnesiens avec les lactols et les lactones. Synthese des diols primaires-secondaires

The reactionz of organomagnesium compounds with cyclic lactols and the phthalde show a high chemioselectivity and provide respectively corresponding monoalkylated cyclic lactones and diols We also observe that the formation of bridged tricyclic lactones stereoselectively yields to thetransisomer. In the same way, we describe an easy and general method for the synthesis of diols, precursors of dibromides and cyclic ethers.