4-Aryl- and 4-vinyl-2,2-dialkyl-3-chromenes from tertiary 3-(o-bromophenyl)propynols via a palladium-catalyzed hydroarylation/hydrovinylation-cyclization sequence

4-Aryl- and 4-vinyl-2,2-dialkyl-3-chromenes were prepared from tertiary 3-(o-bromoplienyl)propynols and aryl iodides or vinyl triflates through a one-pot process, which involves the addition of t-BuONa, dppf and, where appropriate, fresh Pd(OAc)(2) to the crude Mixture resulting from the hydroarylation or hydrovinylation step [Pd(OAc)(2), Et3N, HCOOH, BU4NCI, toluene]. In general, 4-aryl- and 4-vinyl-2,2-dialkyl-3-chromenes are obtained with high regioselectivity and overall yields range from satisfactory to high. Vinyl triflates tend to give higher yields than aryl iodides.