| Summary: | Abstract The scale-up of the ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR) of ( rac )-1-phenylethanol ( 2 ) is addressed. The immobilized lipase Candida antarctica lipase B (CALB) was employed for the resolution, which shows high enantioselectivity in the transesterification. The ruthenium catalyst used, ( η 5 -C 5 Ph 5 )RuCl(CO) 2 1 , was shown to possess very high reactivity in the " in situ " redox racemization of 1-phenylethanol ( 2 ) in the presence of the immobilized enzyme, and could be used in 0.05 mol% with high efficiency. Commercially available isopropenyl acetate was employed as acylating agent in the lipase-catalyzed transesterifications, which makes the purification of the product very easy. In a successful large-scale DKR of 2, with 0.05 mol% of 1, ( R )-1-phenylethanol acetate ( 3 ) was obtained in 159 g (97% yield) in excellent enantiomeric excess (99.8% ee).
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