cas 32345-59-8, 2-CHLORO-MANDELIC ACID METHYL ESTER

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Calcium(II)-mediated resolution of methyl o-chloromandelate with chiral O,O′-dibenzoyltartaric acid in preparative scale
We report here the coordination-mediated resolution of methyl o-chloromandelate, which is a key intermediate for clopidogrel, in preparative scale. The reaction of CaO, optically pure (2R, 3R)-O,O′-dibenzoyltartaric acid, and methyl o-chloromandelate in ethanol solution afforded a mixed-ligands calcium(II) complex that was further purified by stirring of the crystals in hot methanol. Methyl (R)-o-chloromandelate was obtained in good enantiomeric excess value (>99.5%) and yield (71%) by treatment of the complex with acid. At the same time, (2R, 3R)-O,O′-dibenzoyltartaric acid was recovered in 72% yield. In addition, methyl (S)-o-chloromandelate was obtained in good enantiomeric excess value (>99.5%) and yield (73%) by recovery from the mother liquor and resolution with the same procedure for methyl (R)-o-chloromandelate, except that (2S, 3S)-O,O′-dibenzoyltartaric acid was used as the resolving reagent.
Xu, Hong-Wu,Wu, Li-Huan,Ren, Qiang,Liu, Cui-Yu,Yan, Guan-Qing
p. 19 - 22
(2019)
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Improved o-chlorobenzoylformate bioreduction by stabilizing aldo-keto reductase YtbE with additives
Asymmetric reduction of methyl o-chlorobenzoylformate (CBFM) using aldo-keto reductase YtbE is a potentially cost-effective and green technology in manufacturing methyl (R)-o-chloromandelate which is a key intermediate for synthesizing (S)-clopidogrel (a
Xu, Yan-Peng,Guan, Yue Hugh,Yu, Hui-Lei,Ni, Yan,Ma, Bao-Di,Xu, Jian-He
p. 108 - 114
(2014)
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Thienopyridine derivative, preparation method and application thereof
The invention relates to a thienopyridine derivative, a preparation method and application thereof. The thienopyridine derivative has a structure shown in the formula (I), wherein the group R1, R2, R3, R4, X1, X2 or X3 and m, n and w are as defined in the
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Paragraph 0056-0057

(2021/05/12)

Application of the redox system of Nocardia corallina B-276 in the enantioselective biotransformation of ketones and alcohols
The aim of this research was to evaluate the redox system of Nocardia corallina B-276 in the biotransformation of 1-phenyl-1-propanone (1a), 2-hydroxy-1-phenylethanone (2a) and methyl (2-chlorophenyl)(oxo)acetate (3a) into 1-phenylpropan-1-ol (1b), 1-phenyl-1,2-ethanediol (2b) and methyl (2-chlorophenyl)(hydroxy)acetate (3b). The biomass of N. corallina was obtained in a liquid medium with an initial pH of 8.50, but the pH changed during the 96 h of the culture media, the final pH was between 4.74 and 7.62. The N. corallina biomass biocatalyzed the enantioselective reduction of 1a–3a to the corresponding alcohols. Whereas, during the process of oxidation of the rac-alcohols 1b–3b, 1b was oxidized in enantioselective way, the oxidation of 2b was not selective, but 3b was biotransformed mainly to (R)-3b. These results are indicative that N. corallina produced reductases and oxidases, whereby the biocatalytic activity was influenced by the final pH of the culture media, the reaction time and structure of the substrate.
Alvarez, Norberto Manjarrez,Pérez Méndez, Herminia I.,Oba, Aida Solís,Cabello, Lucía Ortega,Lara Carvajal, María T.,Valencia Ledezma, Omar E.,Martínez-Casares, Rubria M.
p. 279 - 290
(2020/06/01)

A preparation method of clopidogrel hydrogen sulfate type II
The invention discloses a preparation method of clopidogrel hydrogen sulfate type II. The method comprises the following steps: (4) taking clopidogrel free alkali as a raw material, and reacting the clopidogrel free alkali with (1R)-(-)-10-camphorsulfonic acid in a reaction solvent to obtain clopidogrel camphorsulfonate, and hydrolyzing under an alkaline condition to obtain clopidogrel free alkali; and then preparing the clopidogrel hydrogen sulfate type II by taking the clopidogrel free alkali obtained in the step (4) as a raw material. The synthetic route is simple, the used solvent is cheap, the cost is saved, the generation of waste liquid is reduced, the recycling of the solvent is improved, and the prepared clopidogrel hydrogen sulfate type II has the characteristics of high purity,good quality, high yield, good stability, suitability for industrial mass production and the like.
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Paragraph 0097-0100; 0116; 0117

(2019/07/11)

A preparation method of clopidogrel hydrogen sulfate type II
The invention discloses a preparation method of clopidogrel hydrogen sulfate type II. According to the method, clopidogrel hydrogen sulfate type II is prepared by taking clopidogrel free alkali as a raw material, and a preparation method of clopidogrel free alkali comprises the following steps: (1) preparing a reaction mixed solution of R-chloromandelic acid methyl ester by the reaction of R-chloromandelic acid and methanol in an organic solvent and in the presence of a catalyst; (2) mixing the reaction mixed solution of R-chloromandelic acid methyl ester with an organic base and a catalyst, reacting in the presence of benzenesulfonyl chloride to obtain a reaction mixed solution of methyl 2-benzenesulfonyl-2-chlorophenylacetate; (3) mixing the reaction mixed solution of methyl 2-benzenesulfonyl-2-chlorophenylacetate obtained in the step (2) with 4,5,6,7-Tetrahydrothieno[3,2,c] pyridine hydrochloride and potassium carbonate for reaction to obtain the clopidogrel free alkali. According to the method, the solvent does not need to be supplemented in the last two steps, the solvent is directly used, and the reaction liquid concentration time is saved.
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Paragraph 0114-0117; 0131-0138

(2019/07/11)

Discovery of 7-hydroxyaporphines as conformationally restricted ligands for beta-1 and beta-2 adrenergic receptors
A series of (-)-nornuciferidine derivatives was synthesized and the non-natural enantiomer of the aporphine alkaloid was discovered to be a potent β1- and β2-adrenergic receptor ligand that antagonized isoproterenol and procaterol induced cyclic AMP increases from adenylyl cyclase, respectively. Progressive deconstruction of the tetracyclic scaffold to less complex cyclic and acyclic analogues revealed that the conformationally restricted (6a-R,7-R)-7-hydroxyaporphine 2 (AK-2-202) was necessary for efficient receptor binding and antagonism.
Ku, Angela F.,Cuny, Gregory D.
supporting information
p. 353 - 356
(2018/03/08)

Optically active 2-hydroxy tetrahydro Thienopyridine derivatives and process for their preparation and use
The invention provides an optically active 2-hydroxyltetrahydrothienopyridine derivative shown by formula I, or a pharmaceutically acceptable salt, solvate, polycrystal, enantiomer or racemization mixture thereof, wherein in the formula I, R1 is F, Cl, Br
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Paragraph 0058; 0061-0063

(2017/01/23)

Improved apparent enantioselectivity of a hydrolase by sequential hydrolysis and racemization
Further improvement of the enantioselectivity of hydrolases with moderate enantioselectivity is of important significance to fulfill the requirement in industrial application. Herein, a strategy based on sequential hydrolysis and racemization was adopted, using esterase BioH from Escherichia coli as an example. After coupling with a mandelate racemase, the E value of esterase BioH toward methyl (S)-o-chloromandelate was enhanced from 73 to 162, demonstrating the effectiveness of this strategy.
Gu, Jiali,Ye, Lidan,Guo, Fei,Lv, Xiaomei,Lu, Wenqiang,Yu, Hongwei
supporting information
p. 1489 - 1491
(2015/03/14)

Altering the substrate specificity of reductase CgKR1 from Candida glabrata by protein engineering for bioreduction of aromatic α-keto esters
A versatile keto ester reductase CgKR1, exhibiting a broad substrate spectrum, was obtained from Candida glabrata by genome data mining. It showed the highest activity toward an aliphatic β-keto ester, ethyl 4-chloro-3-oxobutanoate (COBE), but much lower activity toward bulkier α-keto esters with an aromatic group, such as methyl ortho- chlorobenzoylformate (CBFM) and ethyl 2-oxo-4-phenylbutyrate (OPBE). By rational design of the active pocket, the substrate specificity of the reductase was significantly altered and this tailor-made reductase showed a much higher activity toward aromatic α-keto esters (～7-fold increase in k cat/Km toward CBFM) and lower activity toward aliphatic keto esters (～12-fold decrease in kcat/Km toward COBE). Meanwhile, the thermostability of the reductase was enhanced by a consensus approach. Such improvements may yield practical catalysts for the asymmetric bioreduction of these aromatic α-keto esters
Huang, Lei,Ma, Hong-Min,Yu, Hui-Lei,Xu, Jian-He
supporting information
p. 1943 - 1948
(2014/07/07)

PHENYL CARBAMATE COMPOUNDS FOR USE IN PREVENTING OR TREATING PEDIATRIC EPILESY AND EPILESY-RELATED SYNDROMES
The present invention provides a pharmaceutical composition for preventing and/or treating a pediatric epilepsy or epilepsy-related syndrome comprising the phenyl carbamate compound as an active ingredient, and a use of the phenyl carbamate compound for p
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Page/Page column 40

(2014/09/29)

Kinetic resolution of mandelate esters via stereoselective acylation catalyzed by lipase PS-30
By using lipase PS-30 as catalyst, the kinetic resolution of a series of racemic mandelate esters has been achieved via stereoselective acylation. The value of kinetic enantiomeric ratio (E) reached up to 197.5. Substituent effect is briefly discussed.
Chen, Peiran,Yang, Wenhong
supporting information
p. 2290 - 2294
(2014/04/17)

ANTI-THROMBOTIC COMPOUNDS
New compounds, namely, (7aS,2'S)-2-oxoclopidogrel and its pharmaceutically acceptable salts thereof are disclosed for treatment or prophylaxis of thrombo-embolism and/or cardiovascular diseases.
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Paragraph 0085; 0086

(2013/03/26)

OPTICALLY ACTIVE 2-HYDROXY TETRAHYDROTHIENOPYRIDINE DERIVATIVES, PREPARATION METHOD AND USE IN MANUFACTURE OF MEDICAMENT THEREOF
Optically active 2-hydroxytetrahydrothienopyridine derivatives represented by Formula I and pharmaceutically acceptable salts, preparation method and use in the manufacture of a medicament thereof are disclosed. The pharmacodynamic experiment results show that the present compounds of Formula I are useful for inhibiting platelet aggregation. The pharmacokinetic experiment results show that the present compound of Formula I can be converted in vivo into pharmacologically active metabolites and are therefore useful for inhibiting platelet aggregation. Therefore, the present compounds are useful for the manufacture of a medicament for preventing or treating thrombosis and embolism related diseases.
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Paragraph 0088; 0089

(2013/07/05)

PHENYLCARBAMATE COMPOUND AND MUSCLE RELAXANT CONTAINING THE SAME
A novel phenylcarbamate compound and a pharmaceutical composition containing the same are provided. More specifically, a novel phenylcarbamate compound, a composition for muscle relaxation containing the phenylcarbamate compound as an active ingredient, a
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Page/Page column 15

(2013/02/28)

PHENYL CARBAMATE COMPOUNDS FOR USE IN PREVENTING OR TREATING EPILESY
A method for treatment or prevention epilepsy comprising administering a phenyl carbamate compound in a pharmaceutically effective amount to a subject in need of treatment or prevention of epilepsy is provided.
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Paragraph 0238; 0239; 0240

(2013/07/05)

Bioreduction of methyl o-chlorobenzoylformate at 500 g L-1 without external cofactors for efficient production of enantiopure clopidogrel intermediate
Biocatalytic reduction of methyl o-chlorobenzoylformate (CBFM) provides a green and direct access to methyl (R)-o-chloromandelate [(R)-CMM], an intermediate for a platelet aggregation inhibitor named clopidogrel. As much as 500 g L-1 of CBFM wa
Ni, Yan,Pan, Jiang,Ma, Hong-Min,Li, Chun-Xiu,Zhang, Jie,Zheng, Gao-Wei,Xu, Jian-He
supporting information; experimental part
p. 4715 - 4717
(2012/09/21)

Stereospecific reduction of methyl o-chlorobenzoylformate at 300 g·L-1 without additional cofactor using a carbonyl reductase mined from Candida glabrata
In order to search for oxidoreductases suitable for the preparation of methyl (R)-o-chloromandelate [(R)-CMM], the key intermediate for clopidogrel, the homologous proteins of Gre2p were expressed in Escherichia coli, among which CgKR1 showed the most satisfactory activity and stereoselectivity towards methyl o-chlorobenzoylformate (CBFM). Using the crude enzyme of CgKR1 and glucose dehydrogenase (GDH), as much as 300 g·L-1 of CBFM was almost stoichiometrically converted to (R)-CMM with excellent enantiomeric excess (98.7% ee). More importantly, the reaction could be performed without external addition of an expensive cofactor. The substrate profile indicates that keto esters serve as the most suitable substrate, which was confirmed by gram-scale preparations. Homology modeling and docking analysis revealed the molecular basis for the high stereoselectivity of CgKR1. These demonstrate not only the feasibility of in silico mining of novel enzymes based on sequence homology but also the applicability of this new reductase for the practical production of optically active (R)-CMM. Copyright
Ma, Hongmin,Yang, Linlin,Ni, Yan,Zhang, Jie,Li, Chun-Xiu,Zheng, Gao-Wei,Yang, Huaiyu,Xu, Jian-He
experimental part
p. 1765 - 1772
(2012/08/08)

Efficient synthesis of a chiral precursor for angiotensin-converting enzyme (ace) inhibitors in high space-time yield by a new reductase without external cofactors
A new reductase, CgKR2, with the ability to reduce ethyl 2-oxo-4-phenylbutyrate (OPBE) to ethyl (R)-2-hydroxy-4-phenylbutyrate ((R)-HPBE), an important chiral precursor for angiotensin-converting enzyme (ACE) inhibitors, was discovered. For the first time, (R)-HPBE with >99% ee was produced via bioreduction of OPBE at 1 M without external addition of cofactors. The space-time yield (700 g·L-1·d -1) was 27 times higher than the highest record.
Shen, Nai-Dong,Ni, Yan,Ma, Hong-Min,Wang, Li-Juan,Li, Chun-Xiu,Zheng, Gao-Wei,Zhang, Jie,Xu, Jian-He
supporting information; experimental part
p. 1982 - 1985
(2012/06/01)

OPTICALLY ACTIVE 2-HYDROXY TETRAHYDROTHIENOPYRIDINE DERIVATIVES, PREPARATION METHOD AND USE IN MANUFACTURE OF MEDICAMENT THEREOF
Optically active 2-hydroxytetrahydrothienopyridine derivatives represented by Formula I and pharmaceutically acceptable salts, preparation method and use in the manufacture of a medicament thereof are disclosed. The pharmacodynamic experiment results show that the present compounds of Formula I are useful for inhibiting platelet aggregation. The pharmacokinetic experiment results show that the present compound of Formula I can be converted in vivo into pharmacologically active metabolites and are therefore useful for inhibiting platelet aggregation. Therefore, the present compounds are useful for the manufacture of a medicament for preventing or treating thrombosis and embolism related diseases.
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Page/Page column 7

(2013/02/27)

PHENYLCARBAMATE COMPOUND AND MUSCLE RELAXANT CONTAINING THE SAME
A novel phenylcarbamate compound and a pharmaceutical composition containing the same are provided. More specifically, a novel phenylcarbamate compound, a composition for muscle relaxation containing the phenylcarbamate compound as an active ingredient, a
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Page/Page column 31

(2012/01/14)

PROCESS FOR PREPARATION OF PHENYL CARBAMATE DERIVATIVES
Provided are a process for the preparation of phenyl carbamate derivatives, useful in the treatment of CNS (central nervous system) disorders, an intermediate in the synthesis of the phenyl carbamate derivatives, and a process for preparation of the inter
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Page/Page column 16

(2012/07/28)

ANTI-THROMBOTIC COMPOUNDS
New compounds, namely, (7aS,2′S)-2-oxoclopidogrel and its pharmaceutically acceptable salts thereof are disclosed for treatment or prophylaxis of thrombo-embolism and/or cardiovascular diseases.
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Page/Page column 9

(2013/02/28)

METHODS FOR THE TREATMENT OR PROPHYLAXIS OF THROMBOSIS OR EMBOLISM
The present invention provides a method of ameliorating the drawbacks of anti-platelet drug named clopidogrel. The method of the resent invention comprises administration of an (S)-oxo-clopidogrel or its derivative of the Formula IIA in its free or pharma
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Page/Page column 19

(2012/03/26)

Efficient reduction of ethyl 2-oxo-4-phenylbutyrate at 620 ?l -1 by a bacterial reductase with broad substrate spectrum
A β-ketoacyl-ACP reductase (FabG) gene from Bacillus sp. ECU0013 was heterologously overexpressed in Escherichia coli and the encoded protein was purified to homogeneity. The recombinant reductase could reduce a broad spectrum of prochiral ketones including aromatic ketones and keto esters and showed the highest activity in the asymmetric reduction of ethyl 2-oxo-4-phenylbutyrate (OPBE). Using E. coli cells coexpressing both FabG and glucose dehydrogenase (GDH) genes, as much as 620 ?L-1 of OPBE was almost stoichiometrically converted to ethyl (S)-2-hydroxy-4-phenylbutyrate [(S)-HPBE] with excellent (>99%) enantiomeric excess. More importantly, the process could be performed smoothly without external addition of an expensive cofactor as usually done and could be scaled up very easily. All these positive features demonstrate the applicability of this reductase for the large-scale production of optically active α-hydroxy acids/esters.
Ni, Yan,Li, Chun-Xiu,Zhang, Jie,Shen, Nai-Dong,Bornscheuer, Uwe T.,Xu, Jian-He
supporting information; experimental part
p. 1213 - 1217
(2011/07/09)

Asymmetric reduction of α-keto esters with Thermus thermophilus NADH-dependent carbonyl reductase using glucose dehydrogenase and alcohol dehydrogenase for cofactor regeneration
The enantioselective synthesis of methyl (R)-mandelate and methyl (R)-o-chloromandelate was investigated using an NADH-dependent carbonyl reductase from Thermus thermophilus (TtADH) and, separately, archaeal glucose dehydrogenase and Bacillus stearothermo
Pennacchio, Angela,Giordano, Assunta,Rossi, Mose,Raia, Carlo A.
supporting information; experimental part
p. 4361 - 4366
(2011/10/08)

Simply air: Vanadium-catalyzed oxidative kinetic resolution of methyl o-chloromandelate by ambient air
Vanadium-catalyzed oxidative kinetic resolution (OKR) of methyl o-chloromandelate 2a, key intermediate of the well-known oral antiplatelet agent (S)-clopidogrel, was achieved by ambient air for the first time. The air oxidation system, which was composed of vanadium and tridentate Schiff base ligands derived from amino alcohols and salicylaldehyde derivatives, afforded an efficient and economic approach to the target intermediate with high enantioselectivities (>99% ee).
Yin, Lu,Jia, Xian,Li, Xing Shu,Chan, Albert S.C.
experimental part
p. 774 - 777
(2011/11/12)

Enantioselective iron-catalysed O-H bond insertions
The ready availability, low price and environmentally benign character of iron mean that it is an ideal alternative to precious metals in catalysis. Recent growth in the number of iron-catalysed reactions reported reflects an increasing demand for sustainable chemistry. Only a limited number of chiral iron catalysts have been reported and these have, in general, proven less enantioselective than other transition-metal catalysts, thus limiting their appeal. Here, we report that iron complexes of spiro-bisoxazoline ligands are highly efficient catalysts for asymmetric O-H bond insertion reactions. These complexes catalyse insertions into the O-H bond of a wide variety of alcohols and even water, with exceptional enantioselectivities under mild reaction conditions. The selectivities surpass those obtained with other transition-metal catalysts. This study should inspire and encourage the use of iron instead of traditional precious metals in the development of greener catalysts for catalytic asymmetric synthesis.
Zhu, Shou-Fei,Cai, Yan,Mao, Hong-Xiang,Xie, Jian-Hua,Zhou, Qi-Lin
experimental part
p. 546 - 551
(2010/10/04)

Ru-catalyzed enantioselective preparation of methyl (R)-o-chloromandelate and its application in the synthesis of (S)-Clopidogrel
The preparation of methyl (R)-o-chloromandelate via Ru-catalyzed asymmetric hydrogenation and transfer hydrogenation was investigated. With Ru-(R,R)-2,4,6-triisopropyl C6H2SO2-DPEN as the catalyst and HCOOH-Et3N azeotrope as the hydrogen donor, up to 92% ee was obtained in an optional condition. The synthesis of (S)-Clopidogrel was also studied.
Yin, Lu,Shan, Wenjun,Jia, Xian,Li, Xingshu,Chan, Albert S.C.
experimental part
p. 2092 - 2095
(2009/10/31)

A rapid and green approach to chiral α-hydroxy esters: asymmetric transfer hydrogenation (ATH) of α-keto esters in water by use of surfactants
A series of α-hydroxy esters were rapidly prepared (1.5 h) from α-keto esters via asymmetric transfer hydrogenation (ATH) in water by the use of surfactants for the first time. This green method, catalyzed by a water-soluble and recyclable Ru(II) complex, gave moderate to high enantioselectivities (up to 99.7% ee) with DTAB as an additive and HCOONa as the hydrogen source.
Yin, Lu,Jia, Xian,Li, Xingshu,Chan, Albert S.C.
experimental part
p. 2033 - 2037
(2010/01/16)

Highly efficient chemoenzymatic synthesis of methyl (R)-o-chloromandelate, a key intermediate for clopidogrel, via asymmetric reduction with recombinant Escherichia coli
Methyl (R)-o-chloromandelate [(R)-1], which is an intermediate for a platelet aggregation inhibitor named clopidogrel, was obtained in >99% ee by the asymmetric reduction of methyl o-chlorobenzoylformate (2) with recombinant Escherichia coli overproducing
Ema, Tadashi,Ide, Sayaka,Okita, Nobuyasu,Sakai, Takashi
experimental part
p. 2039 - 2044
(2009/09/25)

THE METHOD OF MAKING OPTICALLY ACTIVE 2-CHLOROMANDELIC ACID ESTERS AND 2-CHLOROMANDELIC ACIDS BY ENZYMATIC METHOD
The present invention relates to process for the preparation of optically active 2-chloromandelic acid esters represented by the general formula 2 and optically active 2-chloromandelic acids represented by the general formula 2 which are used intensively as important chiral intermediates. In more detail, this invention relates to the process for preparing optically active 2-chloromandelic acid esters and optically active 2-chloromandelic acids by stereospecific hydrolysis of racemic 2-chloromandelic acid ester using lipases or lipase-producing microorganisms in the aqeous phase or organic phase including aqeous solvent. The method of making optically active 2-chloromandelic aicd esters and their acids is usful in the practical process because production of seperation of compounds with high optical purity are easy.
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Page/Page column 4

(2008/06/13)

Highly enantioselective and efficient synthesis of methyl (R)-o-chloromandelate with recombinant E. coli: Toward practical and green access to clopidogrel
Methyl (R)-o-chloromandelate ((R)-1), which is an intermediate for a platelet aggregation inhibitor named clopidogrel, was obtained in >99% ee by the asymmetric reduction of methyl o-chlorobenzoylformate (2) (up to 1.0 M) with recombinant E. coli overprod
Ema, Tadashi,Okita, Nobuyasu,Ide, Sayaka,Sakai, Takashi
p. 1175 - 1176
(2008/02/02)

Enantioselective homoallyl-cyclopropanation of dibenzylideneacetone by modified allylindium halide reagents-rapid access to enantioenriched 1-styryl-norcarene
Dibenzylideneacetone (8) reacts with in situ-generated allylindium halide reagents to yield the product of a homoallyl-cyclopropanation reaction: 2-(3″-butenyl)-1,1-bis[(E)-2′-phenylethenyl]cyclopropane (9), which proceeds via step-wise cleavage of the C{double bond, long}O bond and delivery of two allyl fragments from the reagent. A range of enantiomerically enriched ligands have been tested as stoichiometric asymmetric modifiers for this process. Enantiopure compounds such as cinchona alkaloids, ephedra, aminoalcohols and tartaric acid derivatives, which have proven of utility as asymmetric modifiers for the indium-mediated allylation of aldehydes and ketones, were very inefficient in the process 8→9. However, mandelic acid derivatives, in particular mandelates, were found to be of significant potential. The absolute stereochemistry of the cyclopropane 9 has been determined by degradation to 1,1-dicarboxymethyl-2-butylcyclopropane, converging with an independent enantioselective synthesis starting from hexene. Under optimised conditions, viz. using allylindium iodide reagents and working-up with aqueous Na2SO3 to avoid iodine-mediated polymerisation, (S)-9 can be generated in 86% yield and with (S)-methyl mandelate as modifier useful enantiopurity (94/6 er) was observed. The cyclopropane product ((S)-9) undergoes RCM using standard conditions to afford a norcarene unit ((1S,6S)-1-(E)-2′-(phenylethenyl)-bicyclo[4.1.0]hept-2-ene) without loss of enantiopurity.
Lloyd-Jones, Guy C.,Wall, Philip D.,Slaughter, Jennifer L.,Parker, Alexandra J.,Laffan, David P.
p. 11402 - 11412
(2007/10/03)

Enantioselective protonation of samarium enolates derived from α- heterosubstituted ketones and lactone by SmI2-mediated reduction
SmI2-mediated reductive cleavage of α-heterosubstituents of α-alkyl or α-aryl ketones and lactone gave the corresponding 'thermodynamic samarium enolates'. Enantioselective protonation of the samarium enolates with C2- symmetric chiral diols afforded the corresponding ketones and lactone in moderate to high enantioselectivities.
Nakamura, Yutaka,Takeuchi, Seiji,Ohgo, Yoshiaki,Yamaoka, Makoto,Yoshida, Akihiro,Mikami, Koichi
p. 4595 - 4620
(2007/10/03)