Nonconcerted cycloaddition of 2H-azirines to acylketenes: a route to N-bridgehead heterocycles

Alexander F Khlebnikov; Mikhail S Novikov; Viktoriia V Pakalnis; Dmitry S Yufit

doi:10.1021/jo201563b

Nonconcerted cycloaddition of 2H-azirines to acylketenes: a route to N-bridgehead heterocycles

J Org Chem. 2011 Nov 18;76(22):9344-52. doi: 10.1021/jo201563b. Epub 2011 Oct 18.

Authors

Alexander F Khlebnikov¹, Mikhail S Novikov, Viktoriia V Pakalnis, Dmitry S Yufit

Affiliation

¹ Department of Chemistry, Saint-Petersburg State University, 198504 St. Petersburg, Russia. [email protected]

PMID: 21985422
DOI: 10.1021/jo201563b

Abstract

Reactions of acylketenes, generated from diazo diketones, with 2-unsubstituted and 2-monosubstituted 3-aryl-2H-azirines lead to 1:1 or 2:1 adducts, which are derivatives of 5-oxa-1-azabicyclo[4.1.0]hept-3-ene or 5,7-dioxa-1-azabicyclo[4.4.1]undeca-3,8-diene. According to DFT B3LYP/6-31G(d) computations, the formation of (4+2)-monoadducts proceeds via a stepwise non-pericyclic mechanism. Reaction with methanol transforms quantitatively both 1:1 and 2:1 adducts into 1,4-oxazepine derivatives.