- Amine assisted enzymatic esterification of 1,2-diol monotosylates
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The enzymatic esterification of 1,2-diol monotosylates in organic solvent under standard conditions often fails to achieve the desired 50% conversion due to enzyme inactivation by acidic contaminants. The inclusion of an amine affords rapid conversion to
- Boaz,Zimmerman
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p. 153 - 156
(2007/10/02)
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- A Systematic Study on the Bakers'Yeast Reduction of 2-Oxoalkyl Benzoates and 1-Chloro-2-alkanones
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The bakers' yeast reduction of a series of 2-oxoalkyl arenecarboxylates (1a-f) (R=CH3 to n-C6H13; X=H) and the phenyl-modified derivatives (1g-l) (R=n-C5H11, X=OH, CH3, F, Cl, Br, or I) as well as 1-chloro-2-alkanones R(C=O)CH2Cl (6a-f) (R=CH3 to n-C6H13) were systematically investigated.The substrate specificities, configuration and percentee of the reduction products were found to be highly dependent on the length of the alkyl group (R) and the α substituent.Thus, the benzoates 1a-f gave optically active 2-hydroxyalkyl benzoates (2a-f) (R, configuration, percentee) (a: CH3, S, 99; b: C2H5, S, 98; c: C3H7, S, 26; d: n-C4H9, R, 55; e: n-C5H11, S, 15; f: n-C6H13, S, 63) in 11-91percent yields.Among the modification experiments of the phenyl group, 1g-l, the p-iodo substituent markedly increased the ee from 15 to 71percent, although the yield was rather lowered (22percent yield).The reduction of α-chloro ketones 6a-f also gave optically active 1-chloro-2-alkanols (7a-f) in 16-69percent yields.
- Sakai, Takashi,Wada, Kou,Murakami, Takahiko,Kohra, Kiichiro,Imajo, Norihisa,et al.
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p. 631 - 638
(2007/10/02)
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