A Novel Concept in Combinatorial Chemistry in Solution with the Advantages of Solid-Phase Synthesis: Formation of N-Betaines by Multicomponent Domino Reactions

Abstract

Advantages of solid-phase and liquid-phase synthesis are combined in a new concept of combinatorial chemistry: a domino sequence comprising Knoevenagel and hetero-Diels-Alder reactions with subsequent hydrogenation starting from protected aminoaldehydes, 1,3-dicarbonyl compounds, and enol ethers leads to N-heterocycles of high diversity with a betaine structure, which are isolated in highly pure form by precipitation with diethyl ether. Cbz=benzyloxycarbonyl, Bn=benzyl.