Vinyl-stannanes and -silanes having a substituent at the 1 -position react with carbon electrophiles at the terminal position, ie, the normal ips0 electrophilic substitution based on the @-effect is not observed. ... It is generally accepted that the reactions of vinyl-stannanes (la) and -silanes (lb) with electrophiles occur with ipso- substitution, ie, the electrophiles attack the tin (silicon)- bearing vinyl carbon atom regioselectively to produce (2). 1~ In this ...
