30913-86-1Relevant articles and documents
One-Pot Sequential Photoredox Chemistry and Asymmetric Transfer Hydrogenation with a Single Catalyst
Zhang, Xiao,Qin, Jie,Huang, Xiaoqiang,Meggers, Eric
, p. 571 - 577 (2018)
A sequential process is reported, in which different photoredox reactions are placed in sequence with asymmetric transfer hydrogenations of aryl ketones to provide a diverse set of chiral alcohols with enantioselectivities of up to 99 % ee. The method relies on a single chiral-at-metal catalyst which is added at the beginning of the two step sequence and only a final purification of the reaction product is required.
Biocatalytic Asymmetric Reduction of γ-Keto Esters to Access Optically Active γ-Aryl-γ-butyrolactones
??d?o-Dobrowolska, Anna,Borowiecki, Pawe?,Heider, Johann,Kroutil, Wolfgang,Reiter, Tamara,Schühle, Karola,Szaleniec, Maciej,Tataruch, Mateusz,Telatycka, Natalia
, (2020/04/20)
An efficient stereoselective syntheses of a series of functionalized optically active γ-aryl-γ-butyrolactones is achieved by enzymatic asymmetric reduction of the corresponding sterically demanding γ-keto esters employing wild-type and recombinant alcohol dehydrogenases. The best stereoselectivities for the reduction via hydrogen transfer was obtained with two short chain dehydrogenases (SDRs) of complementary stereospecificity from Aromatoleum aromaticum, namely the Prelog-specific NADH-dependent (S)-1-phenylethanol dehydrogenase [(S)-PED] and the anti-Prelog-specific (R)-1-(4-hydroxyphenyl)-ethanol dehydrogenase [(R)-HPED], respectively.Biotransformations catalyzed by both enzymes, followed by TFA-catalyzed cyclization of the resulting γ-hydroxy esters, furnished the respective (S)- and (R)-configured products with exquisite optical purity (up to >99% ee). The synthetic value was demonstrated on preparative scale for the asymmetric bioreduction of the model compound, methyl 4-oxo-4-phenylbutanoate, affording optically pure (S)-γ-phenyl-γ-butyrolactone (>99% ee) in 67–74% isolated yield at 89–95% conversion depending on the applied scale. (Figure presented.).
TBAI/TBHP-Promoted Generation of Malonyl Radicals: Oxidative Coupling with Styrenes Leads to γ-Keto Diesters
Chowdhury, Soumyadeep Roy,Hoque, Injamam Ul,Maity, Soumitra
, p. 2824 - 2828 (2018/09/20)
A metal-free protocol for oxidative coupling of malonic esters with styrenes to form γ-keto diesters has been developed. Key to the success of this process is the generation of malonyl radicals from unfunctionalized malonic esters under organo-catalysis conditions with TBAI and TBHP. This process tolerates both terminal and internal olefins with diverse malonic esters. It provides a new green metal-free alternative to traditional metal mediated process for generation of malonyl radicals and there by γ-keto diesters.