A highly regioselective divergent approach for the phosphine-containing indane/indene derivatives from the ene-yne-oxazolone precursors was reported. An insight into the reaction mechanism involving the phospha-1,4-addition followed by 5-exo-dig ring closure with a concomitant C–P/C–C bond formation was also proposed. This promising protocol utilized H-phosphonate as the phosphonating reagent in a
An efficient one-pot synthesis of fused pyrazoles has been developed. The procedure involved three components reaction of o-alkynylaldehydes 1a-s with ketones 2a-m and hydrazine under mild, metal-free reaction conditions. The desired products were obtained in one-step up to 85% yield. The molecular structure was confirmed by the X-ray crystallographic analysis. (C) 2014 Elsevier Ltd. All rights reserved.