Isotope Effects and Relative Reactivities in the Radical-Chain Addition of Benzenethiol to Substituted Allenes

Article abstract of DOI:10.1021/jo00327a002

The relative reactivities of several monoalkyl- and 1,1-dialkylallenes, one trialkylallene, and one tetraalkylallene toward the addition of phenylthiyl radical have been measured.Isotope effects have been measured for the addition of the phenylthiyl radical to 1,1-dimethylallene and its 3,3-dideuterio and 1,1-bis(trideuteriomethyl) analoques and to ethylallene and its 3,3-dideuterio analoque.The results are interpreted in terms of a very early transition state in which very little rotation about one end of the allene system has occurred.The relative reactivities andproduct distributions are determined by frontier molecular orbital interactions between the singly occupied MO of the phenylthiyl radical and the occupied ? MO's of the allene.