Enantiomerically pure organoseleno-1-arylethanols by enzymatic resolution with Candida antarctica lipase: Novozym 435

Racemic organoseleno-1-arylethanols were prepared by ortho-lithiation of arylethanols, followed by sequential reaction with elemental selenium and alkyl halides and by reaction of either aryldiazonium chlorides with diphenyldiselenide or with lithium and magnesium alkylselenolates. Enantiomerically enriched organoseleno-1-arylethanols were obtained by kinetic resolution of the racemic mixtures by esterification catalyzed by Candida antarctica lipase (Novozym 435). In some cases, enantiomeric excesses of up to 99% were obtained both for alcohols and acetates.

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(−)-(S)-1-(2-(Methylselanyl)-4-methylphenyl)ethanolC10H14OSeEe = 99%[α]D25=-50.7 (c 1.24, CHCl3)Absolute configuration:(S)

(+)-(R)-1-(2-(Methylselanyl)-4-methylphenyl)ethyl acetateC12H16O2SeEe = 99%[α]D25=+40.8 (c 1.57, CHCl3)Absolute configuration:(R)

(+)-(R)-1-(4-(Methylselanyl)phenyl)ethyl acetateC11H14O2SeEe = 99%[α]D25=+127.3 (c 1.4, CHCl3)Absolute configuration:(R)

(−)-(S)-1-(2-(Ethylselanyl)phenyl)ethanolC10H14OSeEe = 99%[α]D25=-54.2 (c 1.4, CHCl3)Absolute configuration:(S)

(+)-(R)-1-(2-(Ethylselanyl)phenyl)ethyl acetateC12H16O2SeEe = 76%[α]D25=+31.35 (c 1.4, CHCl3)Absolute configuration:(R)

(−)-(S)-1-(4-(Ethylselanyl)phenyl)ethanolC10H14OSeEe = 99%[α]D25=-55.4 (c 1.3, CHCl3)Absolute configuration:(S)

(+)-(R)-1-(4-(Ethylselanyl)phenyl)ethyl acetateC12H16O2SeEe = 90%[α]D25=+88.4 (c 1.3, CHCl3)Absolute configuration: (R)

(+)-(R)-1-(3-(Phenylselanyl)phenyl)ethyl acetateC16H16O2SeEe = 90%[α]D25=+43.3 (c 1.2, CHCl3)Absolute configuration: (R)

(+)-(R)-1-(4-(Phenylselanyl)phenyl)ethyl acetateC16H16O2SeEe = 99%[α]D25=+84.4 (c 1.1, CHCl3)Absolute configuration: (R)