Structure and natural bond orbital analysis of oxiranes substituted with agroup 14 element. A comment of SN2 regioselectivity

Crystal structure analysis of oxiranes substituted with a group 14 element revealed that silyl and stannyl groups lengthened their alpha C-O bonds. Na tural bond orbital analysis showed that silyl group raised the energy level of alpha C-O a orbital and lowered that of alpha C-O sigma* orbital. It wa s suggested that the former might lengthen the a C-O bond and that the latt er should affect the regioselectivity in ring-opening reactions.