Rh(II)-carbenoid mediated 2H-azirine ring-expansion as a convenient route to non-fused photo- and thermochromic 2H-1,4-oxazines

Article abstract of DOI:10.1016/j.tet.2013.03.106

The Rh₂(OAc)₄-catalyzed domino reaction of 2H-azirines with 2-acyl-2-diazoacetates provides a unique synthetic approach to non-fused 2H-1,4-oxazines. The reaction proceeds via sequential formation of a rhodium carbenoid, an azirinium