Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/198717
Type: Artigo de periódico
Title: Chemoenzymatic Synthesis Of Alpha-hydroxy-beta-methyl-gamma-hydroxy Esters: Role Of The Keto-enol Equilibrium To Control The Stereoselective Hydrogenation In A Key Step.
Author: Milagre, Cíntia D F
Milagre, Humberto M S
Moran, Paulo J S
Rodrigues, J Augusto R
Abstract: Alpha-hydroxy-beta-methyl-gamma-hydroxy esters not only are found in many natural products and potent drugs but also are useful intermediates in organic synthesis due to their highly functionalized skeleton that can be further manipulated and applied in the synthesis of many compounds with remarkable biological activities. This work was based on a chemoenzymatic approach to obtain these molecules with three contiguous stereogenic centers in a highly enantio- and diastereoselective way. Two distinct linear routes were proposed in which the key steps in both routes consisted of initial stereocontrolled ketoester bioreduction followed by unsaturated carbonyl bioreduction or reduction with Pd-C. Other key reactions in the synthesis include a Wasserman protocol for chain homologation and a Mannich-type olefination with maintenance of enantiomeric excess for all intermediates during the sequence. Whereas route A gave exclusively the skeleton with 3R,4R,5S configuration (99% ee and 11.5% global yield after 7 steps), route B gave the skeleton with 3R,4R,5S and 3R,4S,5R configurations (dr 1:12, 98% ee and 20% global yield after 5 steps).
Subject: Alkenes
Catalysis
Crystallography, X-ray
Cyclization
Esters
Hydrogen-ion Concentration
Hydrogenation
Magnetic Resonance Spectroscopy
Molecular Structure
Phenylpropionates
Stereoisomerism
Rights: fechado
Identifier DOI: 10.1021/jo902227f
Address: http://www.ncbi.nlm.nih.gov/pubmed/20143825
Date Issue: 2010
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File SizeFormat 
pmed_20143825.pdf1.32 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.