A convenient synthesis of phosphonomethyl α,β-unsaturated γ-lactams

A versatile access to diversely substituted α,β-unsaturated γ-lactams is described using a common allylphosphonate precursor. The construction of the γ-lactam motive is based on two steps including a key sequential one-pot Michael addition-Nef sequence that allows the preparation of keto-ester intermediates. Our methodology allowed the selective installation of various alkyl, cycloalkyl and aryl substituents as well as a valuable phosphonomethyl fragment at positions 1 and 3 of the heterocycle.

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