Multicomponent synthesis of γ-nitrocomponds under on water conditions

Abstract

Multicomponent reactions are the most efficient chemical procedures for the synthetic preparation of highly functionalized organic compounds. They take place from raw materials, with great economy of atom, energy-efficient and without intermediate purification steps. That is why the multicomponent reactions, particularly asymmetric multicomponent are of great interest. We have developed a new methodology multicomponent, organocatalytic and scalable which operates in the organic-water interface (conditions >on water>; OW)[2] to obtain γ-nitrocompounds from an aldehyde, a 1,3-dicarbonyl species and a nitroalkane. The reaction proceeds in two steps, a first step in which the 1,3-dicarbonyl species reacts with the aldehyde, resulting in the Knoevenagel adduct and a second step in which the nucleophile nitroalkane is added to this adduct, through a Michael addition. The process requires the presence of catalytic amounts of a thiourea derivative or squaramide (catalyst) and base N,N-Dimethylcyclohexylamine and generates γ-nitroesters featuring three contiguous stereocenters in a single reaction step (see figure 1). These products are suitable γ-amino acid precursor.