Hydrocyanation. Part VIII. Conjugate hydrocyanation of steroidal αβ-unsaturated carboxylic acid derivatives

Abstract

Conjugate hydrocyanation of steroidal αβ-unsaturated carboxylic acid methyl esters with diethylaluminium cyanide, when carried out at about 100°, gives β-cyanocarboxylic esters in low yields. With more reactive αβ-unsaturated carboxylic acid derivatives, the hydrocyanation proceeds smoothly at room temperature to give β-cyanocarboxylic acid derivatives in excellent yields: an αβ-unsaturated acid cyanide and some αβ-unsaturated acid chlorides, on hydrocyanation followed by hydrolysis, are converted into β-cyanocarboxylic acids, and β-cyanothiocarboxylic S-esters are obtained by treating αβ-unsaturated thiocarboxylic S-esters with diethylaluminium cyanide. Stereochemistry and structure–reactivity relationships in these hydrocyanations are discussed.