Umpolung trifluoromethylthiolation of alcohols

Abstract

Herein we developed a metal-free umpolung dehydroxytrifluoromethylthiolation of alcohols with commercially available PPh3 and N-trifluoromethylthiophthalimide within 30 minutes. This protocol shows excellent functional group tolerance and high regioselectivity. The dehydroxytrifluoromethylthiolation...

Direct dehydroxy(sulfhydryl)xanthylation of alcohols and thiols

“…In addition, we found the generation of triphenylphosphine oxide in these tracking experiments, and when the reaction time was extended, the amount of triphenylphosphine oxide increased, accompanied by the consumption of triphenylphosphine. Based on our preliminary mechanistic studies and literature reports, 16,20 a plausible mechanism for the direct dehydroxyxanthylation of alcohols (thiols) was proposed (Scheme 4C). The xanthylphosphonium cation I was quickly generated when PPh 3 attacks the electrophilic N -ethylxanthyl phthalimide 2d .…”

“…Thiols or activated sulfur nucleophilic reagents can participate in the Mitsunobu reaction, producing chiral reversed thioethers or thioesters; 15 b , c however, when we attempted the Mitsunobu reaction with an aliphatic alcohol and potassium ethylxanthate under the activation of trialkyl or triarylphosphine/DEAD, the desired deoxygenated xanthate product was not detected (Scheme 1C, please see the ESI for more details†). Inspired by the successful development of electrophilic phthalimide-based reagents for umpolung Mitsunobu-type functionalization, 16 we wished to employ previously reported N -xanthylphthalimides 17 as electrophilic xanthyl reagents that enable direct dehydroxyxanthylation of naturally rich alcohols to rapidly access the desired alkyl xanthates. The novel umpolung reactivities of electrophilic xanthyl reagents were then demonstrated by the simple dehydroxyxanthylation of a wide range of primary and secondary alcohols in good to excellent yields with superb functional group compatibility under mild conditions (Scheme 1D).…”