N-carbamate protected alpha-amidoalkyl-p-tolylsulfones: convenient substrates in the aza-Morita-Baylis-Hillman reaction

An efficient and practical one-pot approach to aza-Morita-Baylis-Hillman adducts has been developed. The reaction occurs between N-Boc or N-Cbz imines, generated in situ from stable and easy to handle N-Boc or N-Cbz protected alpha-amidoalkyl-p-tolylsulfones, and electron-deficient alkenes in the presence of DABCO. The presented procedure eliminates the use of the relatively unstable N-carbamate imines prior to the coupling reaction. The reaction is limited to alpha-amidosulfones derived from aromatic and heteroaromatic aldehydes.