1335239-47-8Relevant academic research and scientific papers
Regio- and Stereoselective Aliphatic–Aromatic Cross-Benzoin Reaction: Enzymatic Divergent Catalysis
Beigi, Maryam,Gauchenova, Ekaterina,Walter, Lydia,Waltzer, Simon,Bonina, Fabrizio,Stillger, Thomas,Rother, D?rte,Pohl, Martina,Müller, Michael
, p. 13999 - 14005 (2016)
The catalytic asymmetric synthesis of chiral 2-hydroxy ketones by using different thiamine diphosphate dependent enzymes, namely benzaldehyde lyase from Pseudomonas fluorescens (PfBAL), a variant of benzoylformate decarboxylase from?Pseudomonas putida (PpBFD-L461A), branched-chain 2-keto acid decarboxylase from Lactococcus lactis (LlKdcA) and a variant of pyruvate decarboxylase from Acetobacter pasteurianus (ApPDC-E469G), was studied. Starting with the same set of substrates, substituted benzaldehydes in combination with different aliphatic aldehydes, PfBAL and PpBFD-L461A selectively deliver the (R)- and (S)-2-hydroxy-propiophenone derivatives, respectively. The (R)- and (S)-phenylacetylcarbinol (1-hydroxy-1-phenylacetone) derivatives are accessible in a similar way using LlKdcA and ApPDC-E469G, respectively. In many cases excellent stereochemical purities (>98 % enantiomeric excess) could be achieved. Hence, the regio- and stereochemistry of the product in the asymmetric aliphatic–aromatic cross-benzoin reaction can be controlled solely by choice of the appropriate enzyme or enzyme variant.
Stereoselective reduction of 2-hydroxy ketones towards syn- and anti-1,2-diols
Husain, Syed Masood,Stillger, Thomas,Duenkelmann, Pascal,Loedige, Melanie,Walter, Lydia,Breitling, Elke,Pohl, Martina,Buerchner, Mara,Krossing, Ingo,Mueller, Michael,Romano, Diego,Molinari, Francesco
supporting information; experimental part, p. 2359 - 2362 (2011/10/19)
Stereoselective reduction of 2-hydroxy ketones should in principle give access to syn- and anti-1,2-diols. anti-1,2-Diols are accessible in a highly selective way using zinc borohydride [Zn(BH4)2] under chelation control (dr>20:1). Diastereoselective reduction of unprotected or even protected 2-hydroxy ketones towards syn-1,2-diols could be achieved only with moderate selectivity of dr≤5:1. Even when using sterically demanding protecting groups and/or polymer-supported borohydride reagents high selectivity could not be achieved. A new ionic liquid-dependent borohydride reduction method, although highly attractive with respect to reaction engineering, resulted in only moderate to good selectivity. An efficient two-step biocatalytic method for the synthesis of syn-1,2-diols is described. The method relies on the whole-cell Pichia glucozyma-catalyzed stereoselective reduction of the unprotected (R)-2-hydroxy ketones (dr>10:1). The latter are accessible through thiamine diphosphate-dependent enzyme-catalyzed synthesis starting from simple aldehydes. Thus, biocatalytic transformations enable a process which is hardly accessible through present non-enzymatic methods. Copyright
