Non-racemizing synthesis and stereoselective reduction of chiral α-amino ketones

Copper-catalyzed α-amination of aliphatic aldehydes

A highly efficient copper-catalyzed α-amination of aliphatic aldehydes for the synthesis of α-amino acetals using secondary amines with readily removable protecting groups as a nitrogen source was developed. This reaction can be operated under very mild conditions, affording the desired products in moderate to good yields.

A one-flask synthesis of Weinreb amides from chiral and achiral carboxylic acids using the deoxo-fluor fluorinating reagent

[structure] The reagent [bis(2-methoxyethyl)amino]sulfur trifluoride (Deoxo-Fluor reagent) converts carboxylic acids to the corresponding acid fluorides, which then react with N,N-dimethylhydroxylamine to give the corresponding Weinreb amides in high yields. The reaction proceeds without racemization when optically active acids are used as the starting material. This method is operationally simple and provides the products in high purity.

Synthesis and activity of pyrrolidinyl- and thiazolidinyl-dipeptide derivatives as inhibitors of the Tc80 prolyl oligopeptidase from Trypanosoma cruzi

Pyrrolidinyl- and thiazolidinyl- dipeptide derivatives, featuring either a vinyl sulfone-, a 2-ketobenzothiazole-, a nitrile-, or a benzimidazole group at the C-terminus, were designed and synthesized as potential inhibitors of the prolyl-specific Tc80 proteinase from Trypanosoma cruzi, the agent of Chagas' disease. These compounds were evaluated in vitro towards the target enzyme which was classified as a serine protease belonging to the prolyl oligopeptidase family (EC 3.4.21.26). A peptidyl nitrile and two peptidyl alpha-ketobenzothiazoles were shown to be potent reversible and competitive inhibitors of Tc 80 proteinase, with K(i) values in the range 38-219 nM, and compared advantageously with some known mammalian prolyl oligopeptidase inhibitors.

Preparation and Synthetic Applications of Enantiopure (2S,3S)- or (2R,3S)-2-Halomethyl-1,2-epoxyalkan-3-amines

Enantiomerically pure (2S,3S)-3 and its diastereoisomer (2R,3S)-2-halomethyl-1,2-epoxyalkan-3-amine 4 have been obtained from 1-aminoalkyl halomethyl ketones 1 and (iodomethyl)lithium or (chloromethyl)lithium, respectively. Some synthetic applications of compounds 3 are described: chiral unsaturated 1,3-aminoalcohols 8 or 2-(halomethylidene)-3-(dibenzylamino)-alkan-1-ol 11 is obtained from 3 by halogeno-lithium or by hydrogen-lithium exchange, respectively. Transformation of 8c into its methyl ester derivative 9c is also reported.