Gold-catalyzed tandem reaction of o-alkynylphenols with diazo compounds: access to 2,3-disubstituted benzofurans

Abstract

A gold-catalyzed tandem reaction of o-alkynylphenols with diazo compounds has been developed, providing the 2,3-disubstituted benzofurans in moderate to good yields under mild reaction conditions. In this protocol, the vinyl...

Diazo Quinone: An Effective Phenolic Precursor for Building C(sp2)−C(sp2) Bonds

“…[38] Interestingly, the proposed reaction mechanism is different from that shown in Scheme 7. Controlled experiments showed that a coupling reaction between indole 38 and diazo quinone (37) occurred under the current conditions, and oxindole 42 with a C(3) quaternary carbon atom was obtained through cyclopropanation and ring-opening (41). This rules out the reaction pathway of direct nucleophilic attack by indole on Rhquinoid carbene.…”

“…and 49 with diazo quinone gave 2,3-disubstituted benzofurans (50)(51)(52)(53) in moderate to good yields. [41]…”