ONE-ELECTRON AND 2-ELECTRON REACTIONS FROM THE REARRANGEMENT OF ALPHA-KETOCYCLOPROPANES BY O-STANNYL KETYLS

This work summarizes an investigation of the bifunctional reactions of tin(IV) enolates and radicals derived from the cleavage rearrangement of ketocyclopropanes with tributyltin hydride. The intermediates prov ide an unparalleled dual reactivity in synthesis, allowing for indepen dent transformations with both electrophiles and radicophiles. Reactio ns of the enolate with aldehydes led to aldol products in diastereosel ectivities up to 20:1 favoring the erythro product. Reactions with alk yl halides were also successful, constructing new carbon-carbon bonds by a nucleophilic displacement reaction. These reactions provide a neu tral, mild, and novel alternative to the classical methods of ketone e nolate alkylation performed with hindered bases. Finally, the radical portion of the cleaved intermediates, separated from the enolate by a methylene unit, was reacted with allylstannanes to prepare new gamma-c arbon bonds to an allyl unit. Overall, these new trialkyltin-associate d radical anion intermediates allow entry into the rapidly developing manifold of one- and two-electron reactions.