Herein, we introduce Morita–Baylis–Hillman-type yne-allylic esters that serve as novel precursors in a chemodivergent multicomponent reaction platform with carbon-based nucleophiles. SN2″ addition of tertiary amines generates unprecedented vinyl–allenyl ammonium intermediates, whose reactivity is substrate controlled. 1,3-Dicarbonyls afford linear dienol esters via an ABC-type multicomponent reaction (MCR), while aroylacetonitriles trigger a tandem 5 + 1 annulation to give bicyclic lactols. This work provides both a new MCR for drug conjugate synthesis and an efficient route to natural product-like bicyclic lactol scaffolds.
Huang et al. (Wed,) studied this question.