trifluoroacetate gave the acetates (−)-6d and (−)-6f, respectively, with 96–99% ee, and MOM ether (+)-5d with up to 89% ee. Deacetylation of (−)-6d afforded quantitatively MOM ether (−)-5d with 99% ee, the absolute configuration of which was assigned via the modified Mosher method to be (R) at C(6). Enzymatic treatment of unprotected diol 2a with vinyl trifluoroacetate or alkoxycarbonylation resulted in the
Selective Alkoxycarbonylation of A-Ring Precursors of Vitamin D Using Enzymes in Organic Solvents. Chemoenzymatic Synthesis of 1α,25-Dihydroxyvitamin D<sub>3</sub> C-5 A-Ring Carbamate Derivatives<sup>1</sup>
作者:Miguel Ferrero、Susana Fernández、Vicente Gotor
DOI:10.1021/jo970133b
日期:1997.6.1
of vitamin D-related structures. An efficient synthesis of 1alpha,25-(OH)(2)-D(3) C-5 A-ring carbamate derivatives 19 and aminoacidderivatives 21 was developed by applying a two-step chemoenzymatic strategy, involving the enzymatic synthesis of carbonates followed by reaction with aminoderivatives. Accordingly, we began the studies of enzymatic alkoxycarbonylation of 1alpha,25-(OH)(2)-D(3) A-ring
A novel and convenient route to 3'-carbonates from unprotected 2'-deoxy nucleosides through an enzymic reaction
作者:Franciso Moris、Vicente Gotor
DOI:10.1021/jo00034a056
日期:1992.4
Zinner, Chemische Berichte, 1958, vol. 91, p. 302,306
作者:Zinner
DOI:——
日期:——
Lipase-mediated alkoxycarbonylation of nucleosides with oxime carbonates.
作者:Francisco Morís、Vicente Gotor
DOI:10.1016/s0040-4020(01)92279-3
日期:1992.11
5'-O-carbonates of ribonucleosides and 2'-deoxyribonucleosides could be obtained by enzymatic alkoxycarbonylation with SP 435 lipase (from Candida antarctica) and oxime carbonates, which are easily prepared from chloroformates. Ribonucleosides gave as result two kind of 5'-O-carbonates depending on whether alkoxy or acetone oxime moiety acted as the leaving group. In the case of 2-deoxynucleosides, the leaving group was always the acetonoxime moiety, giving rise to regioselective formation of the corresponding 5'-O-alkyl carbonates, together with small amounts of 3'-O-regiosiomer and diacylated compounds.