Stereocontrolled Synthesis of 13-Substituted Retinoic Acids by Palladium-Catalyzed Coupling Reaction of Alkenyl Stannane with Vinyl Triflate
作者:Akimori Wada、Kouki Fukunaga、Masayoshi Ito
DOI:10.1055/s-2001-14908
日期:——
A novel method for the stereoselective synthesis of all-E-, 13Z- and 9Z-retionic acid esters was developed by palladium-catalyzed cross coupling reactions of tetraenyl stannanes with E- or Z-vinyl triflates in good yields. Applying this methodology, 13-substituted all-E- and 9Z-retionic acids were prepared in satisfactory yields.
Stereoselective Synthesis of Acetoacetate-Derived Enol Triflates
作者:David Babinski、Omid Soltani、Doug E. Frantz
DOI:10.1021/ol8010002
日期:2008.7.3
A highly stereoselective method for preparing ( Z)- and ( E)-enol triflates derived from substituted acetoacetate derivatives is described. The salient feature of this methodology is the use of Schotten-Baumann-type conditions to control enolate geometry using either aqueous LiOH ( Z-selective) or aqueous (Me)(4)NOH ( E-selective) in combination with triflic anhydride to provide a practical and predictable
Chemoenzymatic Asymmetric Synthesis of Pregabalin Precursors via Asymmetric Bioreduction of β-Cyanoacrylate Esters Using Ene-Reductases
作者:Christoph K. Winkler、Dorina Clay、Simon Davies、Pat O’Neill、Paul McDaid、Sebastien Debarge、Jeremy Steflik、Mike Karmilowicz、John W. Wong、Kurt Faber
DOI:10.1021/jo302484p
日期:2013.2.15
The asymmetric bioreduction of a library of beta-cyanoacrylate esters using ene-reductases was studied with the aim to provide a biocatalytic route to precursors for GABA analogues, such as pregabalin. The stereochemical outcome could be controlled by substrate-engineering through size-variation of the ester moiety and by employing stereochemically pure (E)- or (Z)-isomers, which allowed to access both enantiomers of each product in up to quantitative conversion in enantiomerically pure form. In addition, stereoselectivities and conversions could be improved by mutant variants of OPR1, and the utility of the system was demonstrated by preparative-scale applications.
Preparation and biological activity of 13-substituted retinoic acids
13-Demethyl or 13-substituted all-E- and 9Z-retinoic acids were synthesized using a palladium-catalyzed coupling reaction of enol triflates and tributylstannylolefins. Their biological activities were then measured. The 13-ethyl analogs exhibited approximately one-half of the antiproliferative and differentiation-inducing activity of ATRA in HL-60 cells. In contrast, in the 9Z-derivatives, all analogs, except for the 13-butyl derivatives, showed apoptosis-inducing activity. (C) 2004 Elsevier Ltd. All rights reserved.