trans-Selective hydrocyanation of ynoates, ynones and ynoic acids catalyzed by nucleophilic phosphines

trans-Selective hydrocyanation of ynoates and ynones in the presence of TMSCN and an alcohol additive are catalyzed by nucleophilic phosphines. The trisubstituted E-olefin products of anti-addition of hydrogen cyanide to the alkyne are produced with high regio-and stereoselectivity. The alcohol additive reacts with TMSCN to produce hydrogen cyanide in situ. Ynoic acids undergo the phosphine catalyzed hydrocyanation in the presence of TMSCN under aprotic conditions only. In these reactions, TMSCN reacts with the acid to generate hydrogen cyanide and the silyl ester which, unlike the acid, undergoes phosphine catalyzed hydrocyanation and gives the stereo-defined E-2-cyano-acrylic acids after work up. (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The selective hydrocyanation of ynoates and ynones is catalyzed by nucleophilic phosphines in the presence of TMSCN and an alcohol additive. The reaction produces trisubstituted E-olefins with high regio- and stereoselectivity. The alcohol additive reacts with TMSCN to generate hydrogen cyanide in situ, facilitating the reaction process.