Electrophilic α-cyanation of 1,3-dicarbonyl compounds

Electrophilic alpha-cyanation of activated methylene compounds was achieved under mild basic conditions using commercially available TsCN as a CN+ equivalent. A series of 1,3-dicarbonyl compounds, both cyclic and acyclic, were found to be suitable substrates for this transformation. Subjecting 1,1,1-trifluoro-1,3-dicarbonyl compounds to a modified procedure resulted in the formation of alpha-cyano ketones after trifluoroacetyl group fragmentation. An efficient one-pot cyanation/pyrazole formation sequence to 4-cyano pyrazoles from 1,3-diketones has also been developed.