Enantioselective acylation of chiral amines catalysed by serine hydrolases

An Efficient and Practical Chemoenzymatic Preparation of Optically Active Secondary Amines

[reaction: see text] An efficient and practical chemoenzymatic method was developed for the preparation of a variety of chiral secondary amines. Here, oxalamic esters were identified as unique derivatives amenable to the enzyme-catalyzed kinetic resolution of racemic secondary amines. Both enantiomers of the amines were produced in high optical purity and yields after the cleavage of the oxalamic groups.

Efficient dynamic kinetic resolution of secondary amines with Pd on alkaline earth salts and a lipase

Combination of Pd, supported on alkaline earth type supports with a lipase results in a selective catalytic system for dynamic kinetic resolution of benzylic amines.

Chemoenzymatic Preparation of Optically Activetrans-Cyclohexane-1,2-diamine Derivatives: An Efficient Synthesis of the Analgesic U-(−)-50,488

Stereoespecific syntheses of (+/-)-trans-N,N-cyclohexane-1,2-diamines ((+/-)-4 a-g) were carried out from the corresponding (+/-)-trans-N,N-dialkylaminocyclohexanols by successive treatment with mesyl chloride and aqueous ammonia. The stereochemical outcome indicates the formation of a meso-aziridinium ion intermediate. Kinetic resolutions of diamines (+/-)-4 were efficiently accomplished in aminolysis reactions catalyzed by lipase B from Candida antarctica with ethyl acetate as the solvent and acyl donor. Acetamides and the remaining diamines, isolated as the benzyloxycarbonyl derivatives, were obtained with very high ee values (92-99%). One of the carbamates was used as a precursor of the analgesic U-(-)-50,488.