16355-00-3Relevant academic research and scientific papers
One Pot Asymmetric Synthesis of (R)-Phenylglycinol from Racemic Styrene Oxide via Cascade Biocatalysis
Sun, Zai-Bao,Zhang, Zhi-Jun,Li, Fu-Long,Nie, Yao,Yu, Hui-Lei,Xu, Jian-He
, p. 3802 - 3807 (2019)
(R)-Phenylglycinol is an important chiral building block for pharmaceutical and fine chemical industry, and its efficient synthesis from cheap and commercially available starting materials is challenging and highly desirable. Herein, a new three-step one-pot cascade system employing epoxide hydrolase, glycerol dehydrogenase, and ω-transaminase was designed for the asymmetric synthesis of (R)-phenylglycinol from racemic styrene oxide. A cofactor self-sufficient system employing AlaDH/L?Ala was utilized for the regeneration of expensive cofactor NAD+ and removal of by-product pyruvate. Furthermore, in situ product removal by cation resin adsorption was used to drive the thermodynamic equilibrium of the cascade reaction to the direction of product generation. Finally, optically pure (R)-phenylglycinol was successfully produced from racemic styrene oxide with high yield (81.9 %) and excellent enantioselectivity (99 % ee).
Different enantioselective interaction pathways induced by derivatized quinines
Uccello-Barretta, Gloria,Balzano, Federica,Quintavalli, Cristiana,Salvadori, Piero
, p. 3596 - 3602 (2000)
The stereochemistries in solution of the diastereoisomeric complexes formed by quinines modified at the hydroxyl site (9-O-acetylquinine; 9-O- (3,5-dimethoxyphenylcarbamate)quinine) or quinuclidine nitrogen (N- benzylquininium chloride) and each enantiomer of 2-(3',5'-dinitrobenzamido)- 1-phenylethanol have been compared to those of the free compounds by 1H NMR investigations. Completely different interaction models, also involving changes of the free state conformations, have been obtained.
A Comparison of Ligands Proposed for the Asymmetric Dihydroxylation
Crispino, Gerard A.,Makita, Atsushi,Wang, Zhi-Min,Sharpless, K. Barry
, p. 543 - 546 (1994)
Comparative data for several ligands proposed recently for use in the osmium-catalyzed asymmetric dihydroxylation (AD) are presented.
Predictive model for epoxide hydrolase-generated stereochemistry in the biosynthesis of nine-membered enediyne antitumor antibiotics
Horsman, Geoffrey P.,Lechner, Anna,Ohnishi, Yasuo,Moore, Bradley S.,Shen, Ben
, p. 5217 - 5224 (2013)
Nine-membered enediyne antitumor antibiotics C-1027, neocarzinostatin (NCS), and kedarcidin (KED) possess enediyne cores to which activity-modulating peripheral moieties are attached via (R)- or (S)-vicinal diols. We have previously shown that this stereochemical difference arises from hydrolysis of epoxide precursors by epoxide hydrolases (EHs) with different regioselectivities. The inverting EHs, such as SgcF, hydrolyze an (S)-epoxide substrate to yield an (R)-diol in C-1027 biosynthesis, whereas the retaining EHs, such as NcsF2 and KedF, hydrolyze an (S)-epoxide substrate to yield an (S)-diol in NCS and KED biosynthesis. We now report the characterization of a series of EH mutants and provide a predictive model for EH regioselectivity in the biosynthesis of the nine-membered enediyne antitumor antibiotics. A W236Y mutation in SgcF increased the retaining activity toward (S)-styrene oxide by 3-fold, and a W236Y/Q237M double mutation in SgcF, mimicking NcsF2 and KedF, resulted in a 20-fold increase in the retaining activity. To test the predictive utility of these mutations, two putative enediyne biosynthesis-associated EHs were identified by genome mining and confirmed as inverting enzymes, SpoF from Salinospora tropica CNB-440 and SgrF (SGR-625) from Streptomyces griseus IFO 13350. Finally, phylogenetic analysis of EHs revealed a familial classification according to inverting versus retaining activity. Taken together, these results provide a predictive model for vicinal diol stereochemistry in enediyne biosynthesis and set the stage for further elucidating the origins of EH regioselectivity.
Stereochemistry of the Spontaneous, Acid-Catalyzed and Base Catalyzed Hydrolyses of Styrene Oxide
Lin, Bin,Whalen, Dale L.
, p. 1638 - 1641 (1994)
The stereochemical courses of the spontaneous, hydronium ion-catalyzed and hydroxide ion-catalyzed hydrolyses of (R)-styrene oxide have been determined by 1H NMR analysis of the bis-(+)-α-(methoxy-α-trifluoromethyl)phenylacetate diesters of the styrene glycol products from each reaction.The glycol product from the spontaneous reaction of chiral styrene oxide is the result of 93percent inversion and 7percent retention.This result, coupled with published results of 18O-labeling experiments, indicates that essentially all of the styrene oxide that reacts with cleavage of the benzyl C-O bond yields glycol with inversion of stereochemistry at the benzyl carbon.A mechanism involving addition of neutral water concerted with benzyl C-O bond breaking is proposed for this reaction.The glycol product from the acid-catalyzed reaction was determined to be the result of 67percent inversion and 33percent retention at the benzyl carbon.This result, which agrees with one previous publication and contradicts that of another, reflects the stereochemistry of addition of solvent to the benzyl carbon.Consistent with a recent report that 18O-hydroxide attacks the α- and β-carbons of styrene oxide at almost equal rates, styrene glycol from the reaction of chiral styrene oxide with sodium hydroxide was found to be, within experimental error, completely racemic.
One-Pot Three-Step Consecutive Transformation of L-α-Amino Acids to (R)- and (S)-Vicinal 1,2-Diols via Combined Chemical and Biocatalytic Process
Zhang, Jian-Dong,Zhao, Jian-Wei,Gao, Li-Li,Zhao, Jing,Chang, Hong-Hong,Wei, Wen-Long
, p. 5032 - 5037 (2019)
Optically pure vicinal 1,2-diols are versatile chiral building blocks in the fine chemical and pharmaceutical industries. L-α-amino acid is a good feedstock source for high value-added product production since it is inexpensive and renewable. However, conversion of L-α-amino acids to enantioenriched vicinal 1,2-diols remains a significant challenge. In this study, combining a simple chemical process and a three-enzyme cascade biocatalysis system, we have successfully implemented a one-pot sequential process for the transformation of L-α-amino acids into enantiopure vicinal 1,2-diols in aqueous medium. Firstly, the NaBH4-H2SO4 system converted L-α-amino acids to (S)-amino alcohols via amino acid carboxyl reduction. Secondly, the three-enzyme (transaminase, carbonyl reductase and glucose dehydrogenase) cascade biocatalysis system converted amino alcohols to enantiopure vicinal 1,2-diols via amino alcohol deamination, α-hydroxy ketone asymmetric reduction and cofactor regeneration. Taking advantage of the two different reaction systems, chiral vicinal 1,2-diols could be obtained from L-α-amino acids with high yields (69–90 %) and excellent ee values (91–>99 % ee).
Highly enantioselective conversion of racemic 1-phenyl-1,2-ethanediol by stereoinversion involving a novel cofactor-dependent oxidoreduction system of Candida parapsilosis CCTCC M203011
Nie, Yao,Xu, Yan,Mu, Xiao Qing
, p. 246 - 251 (2004)
An economical and convenient biocatalytic process was developed for the preparation of (S)-1-phenyl-1,2-ethanediol (PED), which is a valuable chiral building block for pharmaceuticals and liquid crystals, by stereoselective microbial conversion from the corresponding racemate. As a result of screening bacteria, yeasts, and molds, the enantioselective conversion of racemic PED by Candida parapsilosis CCTCC M203011 was found to be the most efficient process to produce (S)-PED with high optical purity of 98% ee and yield of 92%. By detecting the intermediate produced in the reaction by GC-MS, it was suggested that (S)-enantiomer was produced from the intermediate identified as β-hydroxyacetophenone by asymmetric reduction after stereoselective oxidation of (R)-enantiomer to β-hydroxyacetophenone. After investigating the cofactor requirement and stereospecificity of the reaction catalyzed by the cell-free extract from C. parapsilosis CCTCC M203011, it was found that the stereoselective conversion involved the oxidation of (R)-PED to the intermediate with NADP+ as the cofactor and the reduction reaction that formed the product used NADH as the cofactor, which was catalyzed by a novel cofactor-dependent oxidoreduction system. The NADP+-dependent (R)-specific alcohol dehydrogenase involved in stereoinversion was purified from C. parapsilosis CCTCC M203011, which has a relative molecular mass of 45kD.
Activation and deactivation of Cp*Ir(TsDPEN) hydrogenation catalysts in water
Letko, Christopher S.,Heiden, Zachariah M.,Rauchfuss, Thomas B.
, p. 4927 - 4930 (2009)
The addition of H3PO4 to Cp*Ir(TsDPEN-H), where TsDPEN = H2NCHPhCHPhNTs, is a simple method to obtain a water-soluble hydrogenation catalyst capable of reducing aromatic ketones to their corresponding alcohols in aqueous solutions. Key to the reactivity is the low affinity of the coordinatively unsaturated [Cp*Ir(TsDPEN)]+ for H2PO4. Catalyst degradation proceeds via the protonation of the tosylamido ligand, as was established by the crystallographic characterization of the tosylamine complex [Cp*Ir(NCMe)(HTsDPEN)] 2+.
Rhodium catalysed enantioselective hydroboration of alkenylboronic esters with catecholborane
Wiesauer, Christian,Weissensteiner, Walter
, p. 5 - 8 (1996)
Alkenylboronic esters such as (E)-2-(2-phenylethenyl)-1,3,2-dioxaborolane were subjected to catalytic hydroboration with catecholborane and with use of neutral and cationic rhodium complexes modified by various diphosphine ligands. The resulting 1,2-diboryl intermediate was oxidised with alkaline hydrogen peroxide to give the corresponding 1,2-diol with enantioselectivities up to 79% e.e.
Coupled (R)-carbonyl reductase and glucose dehydrogenase catalyzes (R)-1-phenyl-1,2-ethanediol biosynthesis with excellent stereochemical selectivity
Zhou, Xiaotian,Zhang, Rongzhen,Xu, Yan,Liang, Hongbo,Jiang, Jiawei,Xiao, Rong
, p. 1807 - 1813 (2015)
The biotransformation of 2-hydroxyacetophenone to (R)-1-phenyl-1, 2-ethanediol (PED) by NADH-dependent (R)-carbonyl reductase (RCR) from Candida parapsilosis is slow and gives low yields, probably as a result of insufficient cofactors. To improve the biotransformation efficiency of (R)-PED from 2-hydroxyacetophenon, an enzyme-coupling system containing RCR and glucose dehydrogenase (GDH) was constructed to strengthen NADH-recycling pathway in Escherichia coli, in which the Shine-Dalgarno sequence and the aligned spacing sequence were used as linkers between them. The introduction of glucose dehydrogenase had little affects on the cell-growth. The co-expression conditions of RCR and glucose dehydrogenase was optimized to rebalance their catalytic functions. The ratio of kcat/KM for enzyme-coupling system catalyzing 2-HAP and glucose was about 1.0, suggesting the good balance between the functions of RCR and GDH. The rebalanced system gave excellent performance in (R)-PED biotransformation: an optical purity of 99.9% and a yield of 99.9% at optimal conditions: 35°C and pH 7.0. The introduction of glucose dehydrogenase stimulated increases of 23.8% and 63.8%, in optical purity and yield of (R)-PED, and simultaneously reduced the reaction time two-fold. This work provided a valuable method for efficient chiral alcohol production through protein-expression and biotransformation optimization to rebalance cofactor pathways.
