Synthesis of all stereoisomers of cognac lactones via microbial reduction and enzymatic resolution strategies
摘要:
Both enantiomers of the diastereomeric cognac lactones have been synthesised using enzyme assisted reactions in the enantiodifferentiating step. This was accomplished by baker's yeast reduction of their precursors 3-methyl-4-oxononanoic acid and ester and by enzymatic hydrolysis of the latter. An inhibition of hydrolases by the products was observed. Trans-(+)-, trans-(-)-, cis-(+)- and cis-(-)-cognac lactones having 99, 88, 88 and 99% e.e., respectively, were thus obtained. Their CD spectra have also been studied. (C) 2001 Elsevier Science Ltd. All rights reserved.
The synthesis of opticallyactive 4-methyl-5-n-butyl- and 5-n-pentylpyrrolidin-2-ones, aza analogues of the corresponding Quercus lactones, has been achieved by a chemoenzymatic procedure, involving in the enantiodifferentiating step the enzymatic kinetic resolution of the corresponding γ-ketoester precursors, followed by reductive amination and subsequent cyclization of the enantiomerically pure hydrolysis
The lipase catalyzed hydrolysis of cyanomethyl 3-substituted-4-oxoesters was studied. With 3-methyl substituted esters, PPL led to optically active compounds. When the 3-substituent was a larger group, more satisfactory results were obtained with PL, especially if the substituent attached to the ketone function is other from methyl.