First example of regioselective nucleophilic 1,6-addition of trimethyl(trifluoromethyl)silane to 4H-chromene derivatives

Condensation of 2-trifluoromethylchromone with diethyl malonate, ethyl cyanoacetate, and Meldrum’s acid gave the corresponding methylidene derivatives of 2-trifluoromethyl-4H-chromene. Nucleophilic 1,6-addition of an excess of Me3SiCF3 in the presence of Me4NF to those obtained from the former two compounds afforded 4-substituted 2,2-bis(trifluoromethyl)-2H-chromenes.