Benzofuran synthesis via copper-mediated oxidative annulation of phenols and unactivated internal alkynesElectronic supplementary information (ESI) available. See DOI: 10.1039/c3sc51489g

The first example of copper-mediated oxidative annulation of phenols and unactivated internal alkynes to afford benzofuran derivatives was reported. Various phenols and unactivated internal alkynes were successfully employed. Mechanistic studies disclosed a new strategy on annulations of alkynes with phenols through reversible electrophilic carbocupration of phenol followed by alkyne insertion and cyclization. The first example of copper-mediated oxidative annulation of phenols and unactivated internal alkynes was reported to form benzofuran derivatives.