AN EFFICIENT AND STEREOSELECTIVE SYNTHESIS OF(Z)-ALLYL CHLORIDES FROM BAYLIS-HELLMAN ADDUCTS USING VILSMEIER-HAACK REAGENT

摘要

The Vilsmeier-Haack reagent(halomethyleneiminium salt)formed from treatment of dialkylformamides such as DMF with POCl3 has been an old but useful reagent since its discovery in 1927.It is usually used as reagent for the introduction of an aldehydic(CHO)group into aromatic or heteroaromatic compounds;other new applications including halogena-tion,alkylation and haloalkylation have been recently reported.The Baylis-Hillman reaction has received much attention as a useful carbon-carbon bonding-formation reaction in the last decades because it possesses several basic properties of efficient synthetic reactions:atom economy,selective transformations and catalytic process.The adducts,3-hydroxy-2-methyl enealkanoates(derived from acry late esters),have been utilized as important precursors for stereoselective synthesis of different multifunctional molecules.