BETA-ACYLVINYL INTERMOLECULAR RADICAL ADDITIONS TO DOUBLE-BONDS - STEREOSELECTIVE SYNTHESIS OF FUNCTIONALIZED (E)-ALPHA,BETA-UNSATURATED CARBOXYLIC-ACIDS

The reaction of (Z)-3-iodoacrylic acid (1) with a substoichiometric am ount of tributyltin chloride (1:0.5 molar ratio) and an excess of sodi um borohydride (1:4 molar ratio) in the presence of a catalytic amount of AIBN (1:0.18 molar ratio) and an excess of an electrophilic olefin (2) in ethanol leads, after treatment with aqueous sodium fluoride, t o the expected functionalised (E)-alpha,beta-unsaturated carboxylic ac ids 3 in a stereoselective manner. The probable reaction mechanism inv olves free radical intermediates.