Fluoride-induced coupling of perfluoroketene dithioacetals with silyl alkynes: A way towards new polyfunctionalized trifluoromethyl building blocks

Domino nucleophilic trifluoromethylations of alkyl perfluorodithioesters

“…Perfluoroketene dithioacetals 4, 5 undergo fluorideinduced condensation with CF 3 TMS with elimination of fluoride ion to give 6 (two successive condensations in case of 4). We have already reported such type of coupling of perfluoroketene dithioacetals with silyl nucleophiles via nucleophilic chain substitution of the vinylic fluorine [12]. Once formed, 6 is converted into 7 by a last condensation which releases a trifluoromethylsulfanyl anion.…”

Recent Advances in the Synthesis of Thiophene Derivatives by Cyclization of Functionalized Alkynes

“…An interesting approach to multifunctionalized thiophene 16 from 1,1,6,6- tetrakis (ethylthio)-2,5- bis (trifluoromethyl)hexa-1,5-dien-3-yne ( 12 ) has been reported, based on treatment of 12 with a mixture of trifluoroacetic acid and water (TFA-H 2 O 9:3) at 75 °C for 2 h (Scheme 6) [62].…”

“…Synthesis of S -ethyl 2-(5-(ethylthio)-4-(trifluoromethyl)thiophen-2-yl)-3,3,3-trifluoropropanethioate ( 16 ) from 1,1,6,6- tetrakis (ethylthio)-2,5- bis (trifluoromethyl)hexa-1,5-dien-3-yne ( 12 ) through the intermediate formation of 5-(3,3- bis (ethylthio)-1,1,1-trifluoroprop-2-en-2-yl)-2-(ethylthio)-3-(trifluoromethyl)thiophene ( 15 ) [62]. …”

Cross‐Coupling Reactions to sp Carbon Atoms

“…An interesting variant of the sila-Sonogashira-Hagihara reaction avoiding any transition metal catalysts has more recently been reported by Portella et al [332]. The catalytic cycle was implemented under fluoride activation while replacing the vinylic fluorine of the functionalized perfluoroketene dithioacetal 123 with a silylated alkyne to give the alkynylated product 124 in good yield (Scheme 9.45).…”

“…Scheme 9.45Pd-free fluoride-induced coupling of perfluoroketene dithioacetals 123 with alkynyltrimethylsilanes[332].…”