Fig. 3: Substrate scope.

^aYields were based on isolated oxazino pyridines. ^bYield was determined by ¹⁹F NMR using 1-bromo-4-fluorobenzene as the internal standard. DMAD: dimethyl acetylenedicarboxylate. MP: methyl pyruvate. m:d: ratio of mono:di at the meta position. r.r. regioselectivity in the oxazino pyridine (δ:β-selectivity).