Synthesis of symmetrical 1,3-butadiynes by homocoupling reactions of alkynylboronates mediated by a copper salt

An alternative CuCl–piperidine‐catalyzed oxidative homocoupling of terminal alkynes affording 1,3‐diynes in air

“…1,3‐Diynes represent an important class of organic compounds, and the structural motif of 1,3‐diyne has been recognized as an important functionality in molecular materials. Thus numerous synthetic approaches have been developed for the synthesis of 1,3‐diynes, mainly including oxidative homocoupling reactions of terminal alkynes catalyzed by palladium,1–8 nickel9 complexes with the use of copper(I) as co‐catalyst, Cu(I)/(II)‐mediated oxidative homocoupling reactions of terminal alkynes10–15 and homocoupling reactions of alkynylsilanes,16 alkynylboronates17 and potassium alkynyltrifluoroborates,18 and palladium‐catalyzed homocoupling reactions of n ‐butyl alkynyltellurides 19…”

Cu/Fe-Catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling Reactions

“…Terminally silicon substituted alkynes, such as alkynyl silanes were also employed for Glaser homocoupling reactions by Mori et al using catalytic amount of CuCl in DMF (Scheme 1b) [25]. Later, Nishihara reported [26] the similar homocoupling reactions by choosing alkynylboronates as coupling partner in the presence of stoichiometric amount of copper acetate (Scheme 1c). Yadav et al [27] made an improvement by conducting the ligand-assisted copper-catalyzed dimerization of terminal alkynes in the presence of ionic liquid (e.g.…”

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

“…Several methodologies to synthesize 1,3-diynes have been described, employing the dimerization of different starting materials, such as alkynylsilanes (7), alkynyl halides (8), alkynyl Grignard reagents (9), alkynylboronates (10), and potassium alkynyltrifluoroborates (11). In addition, the symmetrical 1,3-diynes are formed as by-products in some crosscoupling reactions, such as the Sonogashira (12) and in the preparation of alkynylchalcogenides (13).…”