Diketo compounds with (trifluoromethyl)trimethylsilane: Double nucleophilic trifluoromethylation reactions

Reactions of various diketo compounds with (trifluoromethyl)trimethylsilane (Me3SiCF3) in the presence of catalytic amounts of cesium fluoride have be en studied. gamma -Ketoesters, CH3COCH2CH2CH2R (R = Et, Bu), were reacted w ith 2 equiv of Me3SiCF3 at room temperature to give CH3C(OH)(CF3)CH2CH2COCF 3 in good yield after hydrolysis. alpha -Diketones, R1COCOR2 (R-1 = R-2 = P h; R-1 = Ph, R-2 = Me; R-1 = R-2 = Me; R-1 = Me, R-2 = Et), when reacted wi th Me3SiCF3, formed 1:1 or 1:2 addition products depending on the reaction conditions and stoichiometry used. Reactions of diones CH3COXCOCH3 (X = -CH 2CH2-, -C6H4C6H4-, -CH2-) with Me3SiCF3 also led to the formation of the mo no- or diaddition products depending on reaction conditions. With various k inds of substituted arylglyoxals, 2 equiv of Me3SiCF3 produced monoaddition products in 70-75% yield and diaddition products in 5-10% yield. One of th e monoalcohols and two of the diols have been characterized by single-cryst al X-ray analysis, and the presence of inter- and intramolecular hydrogen b onding has been confirmed.