Straight-chain ω-amino-α,β-unsaturated carbonyl compounds: versatile synthons for the synthesis of nitrogen-containing heterocycles via organocatalytic reactions

Straight-chain ω-amino-α,β-unsaturated carbonyl compounds have been recognized as versatile organic synthons participating in various organocatalytic reactions for the creation of five- and six-membered saturated nitrogen-containing heterocycles, which are important subunits in a broad range of naturally occurring compounds, biologically active molecules, and drugs. Consequently, these organic synthons have attracted significant interest from synthetic and pharmaceutical chemists, and a series of methodologies and strategies have been efficiently developed. In this review, we elaborate and discuss the recent applications of such versatile synthons according to the following organocatalytic reaction modes: (1) covalent catalysis (secondary amine catalysis, phosphine catalysis, and N-heterocyclic carbene catalysis), (2) non-covalent catalysis (Brønsted acid catalysis), and (3) bifunctional catalysis (bifunctional tertiary amine/primary amine catalysis, bifunctional tertiary amine/squaramide catalysis, and bifunctional tertiary amine/thiourea catalysis).