Hydrogen-Bonding Controlled Nickel-Catalyzed Regioselective Cyclotrimerization of Terminal Alkynes

Herein we report a hydrogen-bonding controlled nickel-catalyzed regioselective cyclotrimerization of terminal alkynes in moderate to excellent yields with high regioselectivities toward 1,3,5-trisubstituted benzenes. This method features a cheap catalyst, mild reaction conditions, and excellent functional group compatibility. The Ni-B(OH)(2) complex in situ generated from NiCl2 center dot DME and tetrahydroxydiboron might act as an active catalyst. After three consecutive cis-additions of terminal alkynes, internal migratory insertion cyclization, and beta-boron elimination induced aromatization, 1,3,5-trisubstituted benzenes were selectively established.

Automated summary

In this study, a hydrogen-bonding controlled nickel-catalyzed regioselective cyclotrimerization of terminal alkynes was reported, yielding 1,3,5-trisubstituted benzenes with high regioselectivities. The method features a low-cost catalyst, mild reaction conditions, and excellent functional group compatibility. The Ni-B(OH)(2) complex generated in situ from NiCl2·DME and tetrahydroxydiboron may act as an active catalyst for this transformation.