Rhodium(iii)-catalyzed C–H activation/[4+3] annulation of N-phenoxyacetamides and α,β-unsaturated aldehydes: an efficient route to 1,2-oxazepines at room temperature†
Abstract
An efficient Rh(III)-catalyzed coupling reaction of N-phenoxyacetamides with α,β-unsaturated aldehydes to give 1,2-oxazepines via C–H activation/[4+3] annulation has been developed. This transformation does not require oxidants and features C–C/C–N bond formation to yield seven-membered oxazepine rings at room temperature. Further derivation of 1,2-oxazepines leads to important chroman derivatives.