TPP‐NBS Induced [3+3] Cascade Annulation of Propargylic Alcohols and 1,3‐Bis Nucleophiles: Access to Chromenopyridines, 1,2‐Dihydropyridines**

Abstract Synthesis of title products were accomplished in a [3+3] annulation of propargylic alcohols and 1,3‐bis nucleophiles. The approach presented herein involves, in situ generation of bromophosphoniumion by the reaction of TPP‐NBS and its reaction with propargylic alcohols resulting in alkoxyphosphoniumion. This, further reacts with 1,3‐bis nucleophiles leading to desired products and liberating HBr. Notably, the liberated HBr found to be involved in driving the reaction to completion. This is the first report with alkoxyphosphoniumion engendered synthesis with the mediation of HBr.