TITANIUM(III) CHLORIDE MEDIATED REDUCTION OF DICYANOALKENES

The reaction of substituted dicyanoalkenes with aqueous titanium(III) chloride was examined. The dicyanoalkenes, which showed irreversible reduction characteristics on cyclic voltammograms, (typically, 2-cyano-3-phenylpropenenitrile), afforded cyclized and/or uncyclized hydrodimers, while those characterized by reversible reduction behavior, (typically, 2-cyano-3,3-diphenylpropenenitrile), yielded the corresponding saturated dinitriles. The reduction mechanism has been rationalized by taking account of the electron transfer from the Ti(III) species to the dicyanoalkenes, followed by protonation, or dimerization and cyclization.