Structure of pyridynes and pyridyne N-oxides and their cycloaddition to ketene dialkyl acetals

The structure of pyridine, pyridine N-oxide, 2-pyridyne, 3-pyridyne, 2-pyridine N-oxide and 3-pyridyne N-oxide have been calculated at the Becke3LYP/6-311 (d,p) level of theory. The regioselectivity of the [2 + 2] cycloaddition of the 3,4-pyridyne to the dimethoxyethylene to give azabenzocyclobutenone dimethyl acetal is in accordance with a biradical pathway. (C) 2004 Elsevier B.V. All rights reserved.