Sequential C-N and C-O Bond Formation in a Single Pot: Synthesis of 2H-Benzo[b][1,4]oxazines from 2,5-Dihydroxybenzaldehyde and Amino acid Precursors

Functionalized beta-aryl alanine ester derivatives were found to undergo rapid C-N and C-O bond formation with quinol carbonyl compounds to afford 2H-benzo[b][1,4]oxazines in good to excellent yields. This unprecedented finding reported herein offers a straightforward, highly efficient, and rapid method for the synthesis of 2H-benzo[b][1,4]oxazines.