Mechanochemical Synthesis of Pyrrole-Substituted Polyynes
Transition-Metal Free Mechanochemical Approach to Polyyne Substituted Pyrroles.
J. Org. Chem. 2016;
17 November 2016 (online)
The authors present a metal-free, mechanochemical synthesis of polyyne-substituted pyrroles. The structurally demanding hexatriynyl- and octatetraynyl-substituted pyrroles were successfully obtained by simple grinding of 1-haloalkynes, pyrroles, and potassium carbonate. This approach is unprecedented in the synthesis of long polyynes.
The reported synthesis exhibits an effective way to obtain pyrrole-end-capped polyynes. Although coupling reactions of pyrroles with 1-haloalkynes are much more efficient using bromides rather than iodides, 1-iodoalkynes were used for the synthesis of longer polyynes in this work because of the poor stability of longer 1-bromoalkynes. The presented polyynes are promising candidates for molecular wire applications.