A convenient method for library construction: parallel synthesis of beta-amino ester and quinoline derivatives in liquid phase using Ln(OTf)3-catalyzed three-component reactions

Yonemitsu-type condensations catalysed by proline and Eu(OTf)3

The reaction of aromatic heterocycles, aldehydes, and active methylene compounds affords polyfunctionalised heterocycles. The reaction is green and provides access to compounds that cannot be obtained by classical methodology.

An efficient and mild bismuth triflate-catalysed three-component Mannich-type reaction

In the presence of a catalytic amount of Bi(OTf)(3).4H(2)O, aldehydes together with amines react with silyl enolates to afford the corresponding Mannich-type adducts smoothly. A wide variety of silyl enolates derived from ketones, as well as esters and thioesters, react rapidly to afford the beta-amino ketones or the beta-amino esters in high yields (up to 94%).

InCl(3)-catalyzed domino reaction of aromatic amines with cyclic enol ethers in water: a highly efficient synthesis of new 1,2,3,4-tetrahydroquinoline derivatives

The tetrahydroquinoline moiety is a structural feature of many natural products. By using a domino reaction of aromatic amines and cyclic enol ethers or 2-hydroxy cyclic ether catalyzed by indium chloride in water, various tetrahydroquinoline derivatives were synthesized efficiently. Most cyclization products showed cis selectivity. The use of 2,3-dihydrofuran as the cyclic enol ether provided both higher reactivity and cis selectivity than the use of 3,4-dihydro-2H-pyran. The cis selectivity was tentatively rationalized due to chelation control in water.

Formation of 1,1'-iminodicarboxylic acid derivatives, 2,6-diketo-piperazine and dibenzodiazocine-2,6-dione by variations of multicomponent reactions

The combination of multicomponent reactions (MCRs) of different amino acids, aldehydes, isocyanides and acids allows complex structures to be prepared in one-pot reactions. The synthesis of 1,1'-iminodicarboxylic acid derivatives 12 demonstrates the high selectivity of the Ugi Four Component Reaction using two different aldehydes and two different isocyanides. The limitations of the MCRs are illustrated by the synthesis of a 1,1'-iminodicarboxylic acid derivative 6 from L-lysine. Furthermore, 2,6-diketopiperazines and dibenzodiazocin-2,6-diones are synthesized via MCRs.