Enantioselective, Catalytic One‐Pot Synthesis of
<i>γ</i>
‐Butyrolactone‐Based Fragrances
作者:Ceyda Kumru、Thomas Classen、Jörg Pietruszka
DOI:10.1002/cctc.201801040
日期:2018.11.7
Herein the preparative (1 g scale), stereoselective syntheses of various alkyl‐substituted γ‐butyrolactone fragrances 1 is described. The α,β‐unsaturated γ‐keto esters 2 as starting materials were synthesized by a Horner‐Wadsworth‐Emmons reaction and are further reduced by an ene reductase and alcohol dehydrogenase in a one‐pot enzyme cascade to nine desired γ‐butyrolactones 1, among them whisky (1 c)
Baker's yeast-mediated approach to (−)-cis- and (+)-trans-Aerangis lactones
作者:Elisabetta Brenna、Claudia Dei Negri、Claudio Fuganti、Stefano Serra
DOI:10.1016/s0957-4166(01)00314-7
日期:2001.7
The first enantioselective synthesis of natural (-)-cis-Aerangis lactone (-)-1a and its (+)-trans-diastereoisomer (+)-lb is described. The key steps in the synthesis are: (i) the enantiospecific and 100% diastereoselective baker's yeast reduction of 1,4-keto acid 2, to afford enantiopure trans- cognac lactone (+)-10; (ii) the regioselective PPL-mediated hydrolysis of the primary acetate moiety of diacetate (+)-(3S,4R)-3, obtained from (+)-10. Chain elongation by one carbon atom via cyanide substitution, and inversion of the configuration of C(5) in nitrile derivative (+)-21a are also required to complete the synthetic route to (-)-1a. (C) 2001 Elsevier Science Ltd. All rights reserved.
GUNTHER C.; MOSANDL A., LIEBIDS ANN. CHEM.,(1986) N 12, 2112-2122