Reactivity and diastereoselectivity of Michael additions of amines to achiral α,β-unsaturated thioamides

Heterocyclic, aliphatic amines add to acyclic and cyclic α,β-unsaturated thioamides yielding β-amino-functionalized derivatives. In the case of cyclic acceptors, the formation of both kinetic and thermodynamically controlled products is observed. Tailoring of cis or trans products is thus possible. A mechanism for the addition to cyclic acceptors is proposed and evidence presented to support it. Ease of addition is studied in relation to the structure of the acceptors.