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Enzymes in organic synthesis, 4. Investigation of the pancreatin‐catalyzed acylation of cis‐cyclopent‐2‐ene‐1,4‐diol with various trichloroethyl and vinyl Alkanoates
Author(s) -
Theil Fritz,
Schick Hans,
Lapitskaya Margarita A.,
Pivnitsky Kasimir K.
Publication year - 1991
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199119910135
Subject(s) - chemistry , acylation , yield (engineering) , vinyl acetate , organic chemistry , acetylation , diol , ethylamine , enantiomeric excess , catalysis , isobutanol , lipase , candida antarctica , enantiomer , benzoic acid , mandelic acid , enzyme , enantioselective synthesis , alcohol , copolymer , biochemistry , materials science , polymer , metallurgy , gene
During the pancreatin‐catalyzed acetylation of the meso‐diol 1 with 2,2,2‐trichloroethyl acetate ( 2a ) in tetrahydrofuran/tri‐ethylamine, the enantiomeric monoacetates 3a and ent‐ 3a are formed at nearly equal rates. ent‐ 3a is rapidly acetylated in a second enzyme‐catalyzed step, forming 4a , whereas 3a resists further enzymatic acetylation. Thus, the monoacetate 3a can be obtained in 48% yield with an enantiomeric excess (e.e.) of more than 99%. 2,2,2‐Trichloroethyl propanoate and butanoate give the corresponding monoacylation products even in slightly better yield, whereas the octanoate affords the mono‐acylation product with a lower enantiomeric excess. 2,2,2‐Trichloroethyl monochloroacetate provides the monoacylation product in a 40% yield with an e.e. of 90%. The dichloroacetate, however, affords the diacylation product exclusively in an enzyme‐independent chemical reaction. With the 2,2,2‐trichloroethyl esters of isobutyric, phenylacetic, and benzoic acid no transesterification could be achieved within 24 hours. The application of vinyl acetate, however, represents a significant improvement in the synthesis of enantiomerically pure monoacetate 3a from meso‐diol 1 .