22584-00-5Relevant articles and documents
Chemoenzymatic asymmetric synthesis of pregabalin precursors via asymmetric bioreduction of β-cyanoacrylate esters using ene-reductases
Winkler, Christoph K.,Clay, Dorina,Davies, Simon,O'Neill, Pat,McDaid, Paul,Debarge, Sebastien,Steflik, Jeremy,Karmilowicz, Mike,Wong, John W.,Faber, Kurt
, p. 1525 - 1533 (2013/04/10)
The asymmetric bioreduction of a library of β-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.
Redox Behavior of Simple Vitamin B12 Model Complexes and Electrochemical Catalysis of Carbon-Skeleton Rearrangements
Murakami, Yukito,Hisaeda, Yoshio,Fan, Sheng-Di,Matsuda, Yoshihisa
, p. 2219 - 2228 (2007/10/02)
Various cobalt complexes of 4,10-dipropyl-5,9-diazatrideca-4,9-diene-3,10-dione dioxime, (C2C3)(DOH)2pn, were prepared, and redox behavior of them was investigated by means of cyclic voltammetry; Co(II)/Co(I) redox potentials in the range of -0.69 through -0.7 V vs.Ag/AgCl.The monomethylated complex, which has a cobalt-carbon bond at one axial site of the nuclear cobalt, was disproportionated to the dimethylated complex, involving two cobalt-carbon bonds at both axial sites, and the CoI species by one-electron reduction.The dimethylated complex was inactive for electrochemical reduction, but transformed into the monomethylated complex via cleavage of a cobalt-carbon bond upon electrochemical oxidation.The electrolyses of 1-bromo-2,2-bis(ethoxycarbonyl)propane, 1-bromo-2-cyano-2-ethoxycarbonylpropane, and 2-acetyl-1-bromo-2-ethoxycarbonylpropane in the presence of IIIBr2> in N,N-dimethylformamide did not proceed in a divided cell at -2.0 vs.Ag/AgCl, since the corresponding dialkylated complexes, inactive for electrochemical reduction, were formed in the course of reaction.When imidazole was added to solutions for the electrolysis, the reaction proceeded efficiently by the trans effect arising from the coordinated axial base and the corresponding carbon-skeleton rearrangement products were obtained.On the other hand, the carbon-skeleton rearrangement proceeded in an undivided cell even in the absence of imidazole; the dialkylated complex was decomposed to give the monoalkylated complex and the reduction and rearrangement products by electrochemical ocxidation on the anode.
Electrochemical Carbon-Skeleton Rearrangements as Catalyzed by Cyano-Coordinated Hydrophobic Vitamin B12
Murakami, Yukito,Hisaeda, Yoshio,Ozaki, Toshiaki,Matsuda, Yoshihisa
, p. 469 - 472 (2007/10/02)
Electrochemical carbon-skeleton rearrangements catalyzed by heptamethyl cobyrinate perchlorate proceeded more efficiently upon coordination of the cyanide ion to the central cobalt atom, and such enhanced catalysis was orihinated from facilitated formatio
