New chemoenzymatic pathway for β-adrenergic blocking agents
摘要:
The lipase mediated kinetic resolution of pharmaceutically important beta-hydroxy nitrites is described in high enantionteric excesses and good yields. Some of the chiral beta-hydroxy nitriles have been employed in the synthesis of P-adrenergic blocking agents such as propranolol, alprenolol and moprolol. This protocol has also been extended for the enantiopure preparation of 5-(4-tosyloxymethyl)-1,3-oxazolidine-2-one and 3-liydroxy-4-tosyloxybutaiieiiitrile, chiral intermediates of high synthetic value. (c) 2005 Elsevier Ltd. All rights reserved.
Efficient Lipase-Catalyzed Kinetic Resolution and Dynamic Kinetic Resolution of β-Hydroxy Nitriles. Correction of Absolute Configuration and Transformation to Chiral β-Hydroxy Acids and γ-Amino Alcohols
Chemoenzymatic dynamickineticresolution of β-hydroxy nitriles 1 has been carried out using Candida antarctica lipase B and a ruthenium catalyst. The use of a hydrogen source to depress ketone formation in the dynamickineticresolution yields the corresponding acetates 2 in good yield and high enantioselectivity. It is shown that the ruthenium catalyst and the enzyme can be recycled when used in