A novel catalyst system-a combination of the readily available 2,2'-biphenol with the inexpensive, nontoxic, and eco-friendly B(OH)3-promoted the Nazarov cyclization of activated and inactivated divinyl ketones to afford the corresponding cyclopentenones up to 96% yield under, in a cis-selective manner. Compared with the conventional harsh conditions with hazardous reagents, user-friendly method was established with bench-stable and easy-to-handle reagents.
Keywords: 2,2′-biphenol; Nazarov cyclization; boric acid; cyclopentenone.