“…The initial stage of this CHg = CHCHgCHgSnBUg + e"^ >• CH^E + Bu^Sn"'" (77) reaction is thought to involve addition of electrophiles to the double 3 bond of the A -butenyl ligand to form electron deficient carbon atom 6 to tin. These incipient carbonium ions then electrophilically induce heterolytic fragmentations of the carbon-tin bond with concurrent ring formation [145]. is more capable than the a-position for accepting a hydrogen atom, it seems that if a 1,2-hydrogen shift were to occur, it would be most reasonable to expect it to yield PhSCHgCHgÔHCHgSnBug rather than PhSCH2CH=CHCH2.…”