Novel 3,4-dihydro-1,4-oxazine (dehydromorpholine) sulfonamides and sulfones conveniently accessed from suitable a-diazoketones via O H carbene insertion – Cyclization sequence

A short and practically convenient, modular approach to hitherto unknown dehydromorpholine sulfones and sulfonamides from α-acyl-α-diazomethyl sulfones and sulfonamides, respectively, has been developed. It involves Rh(II) carbene insertion into the O H bond of 2-bromoethanol followed by thermally promoted tandem SN2 displacement of the bromine atom by a primary amine and cyclodehydration.