New synthesis of symmetrical and asymmetrical conjugated polyacetylenes

Abstract

This method is based on the reaction of cuprous derivs. of C2H2 with Br derivs. of C2H2 compds. (Straus, et al., C.A. 25, 71). When the cuprous deriv. formed in a slightly ammoniacal aq. soln. of EtOH in the cold (-15 Deg to 0 Deg) is slowly treated with the Br deriv. a rapid exothermic reaction occurs. Asym. aliphatic and aromatic diacetylene glycols, diacetylene monoalcs. hydroxydiacetylene acids and triacetylene glycols were obtained. Dimeric analogs can be prepd. by the reaction of Br derivs. of C2H2 with CuCl, which converts a part of the Br deriv. into the corresponding cuprous deriv. which then reacts with excess of the Br deriv. Dimethyloctadienediol and (C.tplbond.CPh)2 were prepd. in 60% yield. [on SciFinder (R)]