CONFORMATIONAL STUDIES OF THE TRIMER AND STEREOISOMERIC TETRAMERS OF NORMAL-BUTYLSILANE

In order to explain the formation of a nonstatistical distribution of stereoisomers in the transition-metal-catalyzed dehydrogenative coupling of n-butylsilane, conformational analyses of the trimer and tetramers of n-butylsilane were carried out by using empirical force-field techniques. Structures of the low-energy conformations of the trimer indicate ready access to each heterotopic hydrogen. Conformational energy maps of the stereoisomeric tetramers indicate only slight differences in the size and shape of the low-energy domains. Therefore, the nonstatistical distribution of stereoisomers appears to arise from intermediate transition-metal complexes as opposed to conformational differences in the trimer and/or the tetramers.