C -> N Migrations of the thoxycarbonyl group in reactions of ortho-substituted aryl isocyanates with the 1,3-zwitterion derived from triisopropylphosphine and ethyl 2-cyanoacrylate

摘要

The reactions of meta-para-substituted aryl isocyanates with phosphorus-containing 1,3-zwitterions, which proceed with the C -> N migration of the CO_2Et group to form the corresponding carbamates, were extended to ortho-substituted aryl isocyanates. The influence of the steric and electronic effects of the ortho substituents in the aromatic rings of aryl isocyanates on the ease of this rearrangement is qualitatively considered.