Divergent Annulation Modes of ()-4-Aryl-4-oxo-2-(pyridin-2-yl)but-2-enenitrile and Methyl Nitroacetate: Selective Access to 2-Acyl-4-quinolizin-4-one, Isoxazole, and 2-Acylindolizine.

Three different annulation modes of ()-4-aryl-4-oxo-2-(pyridin-2-yl)but-2-enenitrile in the reaction with methyl nitroacetate were discovered, allowing selective access to diverse heterocycles such as quinolizin-4-one, isoxazole, and indolizine with unique substitution patterns in good yields. Ease of operation, good chemical yields, and good functional group tolerance of our protocol enabled us to rapidly construct a number of synthetic analogs based on each scaffold under three reaction conditions.