Green synthesis of 1,3-diynes from terminal acetylenes under solvent-free conditions

Abstract

Herein, we report the microwave-assisted synthesis of 1,3-diynes from terminal acetylenes, catalyzed by CuI and tetramethylethylenediamine, in the presence of air as the oxidant, at 100°C for only 10 min under solvent-free conditions. This efficient methodology allowed the homocoupling of several terminal alkynes in moderate to excellent yields. Moreover, the same protocol was also applicable for the synthesis of some unsymmetrical 1,3-diynes through the cross-coupling reaction.

Lignosulfonate/Dicationic Ionic Liquid Composite as a Task-Specific Catalyst Support for Enabling Efficient Synthesis of Unsymmetrical 1,3-Diynes with A Low Substrate Ratio

“…Conjugated 1,3-diynes have been used as important building blocks in organic synthesis, and these kind of molecules also widely exist in natural products, pharmaceuticals and bioactive compounds . Therefore, especially for unsymmetrical diynes, − much attention has been paid to their synthesis. − The present ways to construct conjugated 1,3-diynes include the following five methods: (i) homocoupling of vinyl dibromides, (ii) decarboxylative coupling of vinyl dibromides and alkynyl carboxylates, (iii) elimination of ( Z )-arylvinyl bromides under basic conditions, (iv) decarbonylation of diynones, and (v) Glaser heterocoupling of two different terminal alkynes. − The last method has been widely used in the practical synthesis because of the following two reasons: (i) the starting materials are easily available; and (ii) the reaction conditions are quite mild.…”

Allocation of Ambipolar Charges on an Organic Diradical with a Vinylene–Phenylenediyne Bridge

“…The synthesis of the target diradical (2-R in Scheme 1) started from compound 1-H. 19 First, 2-H was obtained by the coupling of terminal acetylenes in 1-H with catalytic Cu(I). 20 Two different routes (a and b in Scheme 1) were followed to obtain 2H, achieving an excellent reaction yield of up to 92% with route b. 2-R was then prepared almost quantitatively (91%) by deprotonating 2-H to its corresponding dicarbanion and a subsequent oxidation (see Section 3 of the SI for further details).…”

“…The synthesis of the target diradical ( 2-R in Scheme ) started from compound 1-H . First, 2-H was obtained by the coupling of terminal acetylenes in 1-H with catalytic Cu­(I) . Two different routes (a and b in Scheme ) were followed to obtain 2H , achieving an excellent reaction yield of up to 92% with route b.…”