Negishi coupling of metallated difluoroenol derivatives based on trifluoroethanol

Difluorovinylmetal building blocks prepd. from 1-(2'-methoxy-ethoxymethoxy) -2,2,2-trifluoroethane (1a) and 1-(N,N-diethylcarbamoyloxy)-2,2,2-trifluoroethane (1b), have been used in our lab. in syntheses of analogs of biol. significant compds. Access to these useful reagents requires a dehydrofluorination/metalation step at -78°C; however, the seminal work of Donald Burton and co-workers have allowed us to prep. difluorovinylzinc reagents 2a and 2b and iodides 3a and 3b at near ambient temp. and investigate their scope in palladium catalyzed coupling