The reaction of several vinylsilanes with benzonitrile oxide, 2-diazopropane, C-carboethoxy- N-phenylnitrile imine, and substituted 1, 3-butadienes has been examined. The 1, 3-dipolar cycloadditions followed frontier orbital predictions and gave silylated isoxazoles, nonsilylated pyrazolines, and silylated ppazolines, respectively. The orientation observed can be explained in terms of maximum orbital overlap of the dipole LUMO-vinylsilane ...
