Mechanism of the Triphenylphosphine-Tetrachloromethane-Alcohol Reaction: Pericyclic or Clustered Ion Pairs?

Article abstract of DOI:10.1021/jo00330a030

The intermediate formed from tetrachloromethane-triphenylphosphine and neopentyl alcohol decomposes bimolecularly in acetonitrile and not unimolecularly as in CDCl3.This kinetic order is not consistent with a pericyclic pathway but is consistent with an ion-pair mechanism.Consistent with the ion-pair mechanism in acetonitrile is the incorporation of external nucleophiles in the neopentyl skeleton by addition of added nucleophiles to the system.Consistent with the enhanced polarity of acetonitrile is the increased amount of carbon-oxygen cleavage resulting in extensive racemization of the reaction product from (R)-(+)-2-octanol.The preparation of neopentyl thiocyanate and neopentyl isothiocyanate from the corresponding alcohol illustrates the synthetic utility of this reaction in more polar solvents.