L'addition des organomagnesiens aliphatiques satures sur les triples liaisons disubstituees non conjuguees: IV. Influence d'un groupement fonctionnel thioether en α de la triple liaison. Action catalytique du cuivre

Abstract

The addition reaction of ethylmagnesium bromide to the triple bond of the compounds of general formula EtSCH 2C CCH 2Y (where Y is the basic group OH, OR, NR 2, or SEt) is very weakly activated by the thioether group. Catalysis by magnesium impurities may be involved. With 1-ethylthio-4-dialkylamino-2-butynes (Y NR 2), ( E) trisubstituted ethylenic compounds are selectively obtained. The reaction more readily occurs after the addition of cuprous chloride to the Grignard solution, and then its stereoselecitvity may be reversed.