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Kinetic Resolution of 1‐Biaryl‐ and 1‐(Pyridylphenyl)alkan‐1‐ols Catalysed by the Lipase B from Candida antarctica
Author(s) -
Kourist Robert,
GonzálezSabín Javier,
Liz Ramón,
Rebolledo Francisca
Publication year - 2005
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200404330
Subject(s) - candida antarctica , chemistry , transesterification , vinyl acetate , kinetic resolution , acetaldehyde , enantioselective synthesis , lipase , organic chemistry , benzaldehyde , diethylzinc , medicinal chemistry , ethanol , catalysis , stereochemistry , enzyme , copolymer , polymer
Lipase B from Candida antarctica (CAL‐B) catalyses the highly enantioselective ( E >200) transesterification of some 1‐biaryl‐2‐yl‐, ‐3‐yl‐, and ‐4‐ylethanols and ‐propan‐1‐ols, as well as 1‐( o ‐, m ‐, and p ‐pyridylphenyl)ethanols, 6 , with vinyl acetate, Kazlauskas' rule being obeyed in all cases. meta and para ‐Substituted substrates were transformed within several hours (conversion degree ranging from 23–50%), reaction rates for propan‐1‐ol derivatives being slower than those for ethanol derivatives. Transesterifications of ortho ‐substituted alcohols took several days and were accompanied by a chemoenzymatic side reaction: the formation of another acetate derived from the hemiacetal between 6 and acetaldehyde coming from vinyl acetate. This side reaction was suppressed in the presence of isopropenyl acetate as acyl donor, conversion degrees for transesterification ranging from 20–40% after ten days ( E >200). The usefulness of ( R )‐ 6p as ligand in the asymmetric addition of diethylzinc to benzaldehyde was also demonstrated.