A Brønsted acid catalysed enantioselective Biginelli reaction

A Bronsted acid catalysed enantioselective Biginelli reaction

Green Chem., 2017, 19,1529-1535
DOI: 10.1039/C6GC03274E, Paper
Margherita Barbero, Silvano Cadamuro, Stefano Dughera
A chiral derivative of 1,2-benzenedisulfonimide, namely (-)-4,5-dimethyl-3,6-bis(o-tolyl)-1,2-benzenedisulfonimide is herein proven to be an efficient chiral catalyst in a one pot three-component Biginelli reaction.

A Brønsted acid catalysed enantioselective Biginelli reaction

*Corresponding authors
aDipartimento di Chimica, Università di Torino, C.so Massimo d’Azeglio 48, 10125 Torino, Italy
E-mail: stefano.dughera@unito.it
Green Chem., 2017,19, 1529-1535

DOI: 10.1039/C6GC03274E

A chiral derivative of 1,2-benzenedisulfonimide, namely (−)-4,5-dimethyl-3,6-bis(o-tolyl)-1,2-benzenedisulfonimide is herein proven to be an efficient chiral catalyst in a one pot three-component Biginelli reaction. In fact the yields of the target dihydropyrimidines were very high (25 examples; average 91%) and enantiomeric excesses were always excellent (14 examples; average 97%). Ultimately, we herein propose a procedure that displays a number of benefits and advantages including the total absence of solvents, mild reaction conditions, relatively short reaction times and stoichiometric reagent ratios. Target dihydropyrimidines are obtained in adequate purity, making further chromatographic purification unnecessary. Moreover, the chiral catalyst was easily recovered from the reaction mixture and reused, without the loss of catalytic activity.
dihydropyrimidine-2-thiones 5
(R)-(-)-Ethyl 6-methyl-4-phenyl-2-thioxo-3,4-dihydropyrimidine-5-carboxylate (5a): pale grey solid (135 mg, 98% yield); mp 201–202 °C ( from EtOH; lit17 200–202 °C). 96.4% Ee (GC connected to a J&W Scientific Cyclosil-B column; stationary phase: 30% heptakis (2,3-di-Omethyl-6-O-t-butyldimethylsilyl)-β-cyclodextrin in DB-1701), tR= 12.11 min (major), tR= 12.54 min (minor); [a]D -65.4 (c 0.1 in MeOH). 1H NMR (200 MHz, DMSO-d6): δ = 10.24 (br s, 1H), 9.55 (br s, 1H), 7.31–7.12 (m, 5H), 5.09 (d, J = 3.9 Hz, 1H), 3.92 (q, J = 7.0 Hz, 2H), 2.21 (s, 3H), 1.01 (t, J = 7.0 Hz, 3H); 13C NMR (50 MHz, DMSO-d6): δ = 174.9, 165.8, 145.7, 129.3, 128.3, 127.0, 101.3, 60.2, 54.7, 17.8, 14.7. MS (m/z, EI): 276 [M+ ] (45), 247 (40), 199 (100). IR (neat) ν (cm−1): 3311 (NH), 3112 (NH), 1665 (CO), 1195 (CS).
Image result for Stefano Dughera

Dughera Dott. Stefano

Tel: 0116707645
Email: stefano.dughera@unito.it
address: Department of Chemistry

Dipartimento di Chimica, Università di Torino, C.so Massimo d’Azeglio 48, 10125 Torino, Italy

R. Fu, Y. Yang, W. Lai, Y. Ma, Z. Chen, J. Zhou, W. Chai, Q. Wang, and R. Yuan, Synth. Comm., 2015, 45, 477.
//////////////Brønsted acid,  catalysed,  enantioselective,  Biginelli reaction, dihydropyrimidine-2-thiones

A deeper shade of green: inspiring sustainable drug manufacturing

Graphical abstract: A deeper shade of green: inspiring sustainable drug manufacturing

Green and sustainable drug manufacturing go hand in hand with forward-looking visions seeking to balance the long-term sustainability of business, society, and the environment. However, a lack of harmonization among available metrics has inhibited opportunities for green chemistry in industry. Moreover, inconsistent starting points for analysis and neglected complexities for diverse manufacturing processes have made developing objective goals a challenge. Herein we put forward a practical strategy to overcome these barriers using data from in-depth analysis of 46 drug manufacturing processes from nine large pharmaceutical firms, and propose the Green Aspiration Level as metric of choice to enable the critically needed consistency in smart green manufacturing goals. In addition, we quantify the importance of green chemistry in the often overlooked, yet enormously impactful, outsourced portion of the supply chain, and introduce the Green Scorecard as a value added sustainability communication tool.

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C6GC02901A?utm_medium=email&utm_campaign=pub-GC-vol-19-issue-1&utm_source=toc-alert#!divAbstract

The Green Aspiration Level (GAL) has been constructed on four pillars to ensure consistent application, namely (1) clearly defined synthesis starting points,1 (2) unambiguous complete E factor (cEF)2,3 or Process Mass Intensity (PMI) waste metrics, (3) historical averages of industrial drug manufacturing waste, and (4) complexity of the drug’s ideal manufacturing process (Supplementary Figure 6). cEF or PMI can be used interchangeably in GAL-based analysis enabling organizations using either to calculate their green performance scores. cEF and PMI differ by just one unit (Supplementary Equation 6) and share the same commercial waste goal for an average manufacturing step4 – the transformation-GAL or tGAL – that results in negligible numerical differences from the inclusion of one or the other. The pharmaceutical industry has generally adopted PMI. However, our publication utilizes cEF values due to literature prevalence and potentially broader appeal of E factors.5 It is important to note that all reaction and workup materials are included in the analysis, but excluded are reactor cleaning6 and solvent recycling.7 Standardized process starting points are a critical component of the GAL methodology. A starting material for some may be an intermediate for others. Until recently, the scientific community lacked an unambiguous definition of process starting points in the assessment of process greenness. This has been a bothersome source of inconsistency. Failure to define an appropriate starting material can lead to exclusion of significant amounts of intrinsic raw material waste created during earlier stages of manufacture. We therefore utilize these updated definitions of process analysis starting points to ensuring higher quality of data:8

1) The material is commercially available from a major reputable chemical laboratory catalog company, and its price is listed in the (online) catalog. Materials requiring bulk or custom quotes do not qualify as process starting material. AND 2) The laboratory catalog cost of the material at its largest offered quantity does not exceed US $100/mol. Therefore, published literature must be researched if the material does not qualify as process starting material in order to determine its correct intrinsic cEF. However, we realized that determination of literature cEF values is tedious and involves making assumptions since literature procedures are often incomplete compared to internal or external manufacturing batch records. Thus, standardizing Literature cEF quickly became a desirable goal. In order to facilitate literature analysis we introduced Supplementary Equation 7 that just requires determination of literature step count from ≤$100/mol starting materials without having to retrieve literature waste information.9 The literature step multiplier of 37 kg/kg represents the average literature step cEF across the analyzed projects (Supplementary Table 1), so it equals their average literature cEF (76 kg/kg) divided by average literature step count (2.1). The process cEF and Relative Process Greenness (RPG) derived from the simplified calculated cEF literature values are shown next to their progenitors in Supplementary Table 3. We observe that average calculated and manually determined cEF and RPG values are comparable and within 10% of their means across the three development phases. Thus, we consider the simplified method sound and an importtant element to achieving consistency in green process analysis.

str1 str2 str3 str4

A deeper shade of green: inspiring sustainable drug manufacturing

 *Corresponding authors
aChemical Development, Boehringer Ingelheim Pharmaceuticals, Ridgefield, USA
E-mail: frank.roschangar@boehringer-ingelheim.com
bPharmaceutical Sciences – Worldwide Research & Development, Pfizer, Groton, USA
cPfizer, Sandwich, UK
dChemical & Analytical Development, Novartis Pharma, 4002 Basel, Switzerland
eAPI Chemistry, GlaxoSmithKline Medicines Research Centre, Stevenage, UK
fSmall Molecule Process Chemistry, Genentech, a Member of the Roche Group, South San Francisco, USA
gSmall Molecule Design and Development, Eli Lilly and Company, Indianapolis, USA
hChemical and Synthetic Development, Bristol-Myers Squibb, New Brunswick, USA
iProcess Chemistry, Merck, Rahway, New Jersey 07065, USA
jProcess Development, Amgen, Thousand Oaks, USA
kMolecular Sciences Institute, School of Chemistry, University of the Witwatersrand, Johannesburg, South Africa
lDelft University of Technology, 2628 BL Delft, Netherlands
Green Chem., 2017,19, 281-285

DOI: 10.1039/C6GC02901A

Frank Roschangar, PhD MBA

Frank Roschangar, PhD MBA

Pharmaceutical process research director, passionate about accelerating drug development and driving green chemistry.

Boehringer Ingelheim
Ingelheim am Rhein, Germany

Research experience

  • Feb 2002–Sep 2015
     Director
    Boehringer Ingelheim
    Germany · Nieder-Ingelheim
  • Aug 1996–Feb 1998
    Postdoc
    The Scripps Research Institute · Skaggs Institute for Chemical Biology · Prof. K.C. Nicolaou
    United States · La Jolla
  • Aug 1992–Aug 1996
    PhD Candidate
    Rice University · Department of Chemistry
    United States · Houston
Supplementary References
1. The $100 per mol laboratory catalog pricing requirement described in Supplementary Discussion 1 does not apply to reagents, catalysts, ligands, and solvents, since they are produced for widespread application and are not specific to the process being evaluated.
2. Since the original E factor has been applied inconsistently, the cEF metric was introduced for the purpose of GAL analysis. cEF accounts for all process reaction and process workup materials, including raw materials, intermediates, reagents, process aids, solvents, and water.
3. All E factors reported herein represent the cEF or sEF contributions of the overall manufacturing process or the sub-process (e.g. external cEF, literature cEF) to produce 1 kg of drug substance.
4. We define a step as a chemical operation involving one or more chemical transformations that form and/or break covalent or ionic bonds and lead to a stable and isolable intermediate, but not necessarily include its isolation. Examples: • Simultaneous removal of two or more protection groups involves multiple transformations, yet it is carried out in one chemical operation  counted as one step • Sequential transformations via a stable and isolable intermediate that are carried out in two operations but without intermediate workup  counted as two steps • Formation of covalent bonds or salts that occur during workup  not counted as an extra step • Separate operation of salt formation from an isolated intermediate  counted as one step • Isolation of a product, following work-up, as a solution that can be stored  counted as one step.
5. A SciFinder search for the terms ‘Process Mass Intensity’, and ‘E factor’ and ‘Environmental impact factor’ on Nov. 14, 2016 revealed that the PMI concept was present in 12, 8, 9, and 12 publications for the years 2013-2016, respectively, while the E factor concept was mentioned 39, 45, 57, and 46 times (76-86%), respectively.
6. The GAL considers only direct process materials, i.e. materials used in the chemical steps and their workups. It does not include solvents and aqueous detergents required for reactor and equipment cleaning between batches or steps, nor the frequency and duration of the equipment and facility specific cleaning operations. These parameters are considered for comprehensive environmental impact in Life Cycle Assessment (LCA) analysis.
7. In US pharmaceutical manufacturing, recycling accounts for 25% of waste handling, while energy recovery burning and treatment constitute 38% and 35%, based on 2012 data from ‘The Right-To-Know Network’ (RTKNET.ORG), Toxic Releases (TRI) Database: http://rtknet.org/db/tri.
8. The $100 per mol commodity pricing criterion was established in ref. 15 of the main article based on the author’s professional experience. The authors of this manuscript consider this figure appropriate and helpful for providing a consistent analysis.
9. If a detailed procedure is available for a particular literature step, its calculated waste can be used in place of the 37 kg/kg default value.
10. J. Li and M. D. Eastgate, Current Complexity: a Tool for Assessing the Complexity of Organic Molecules. Org. Biomol. Chem. 2015,13, 7164–7176.
11. D. P. Kjell, I. A. Watson, C. N. Wolfe and J. T. Spitler, Complexity-Based Metric for Process Mass Intensity in the Pharmaceutical Industry. Org. Process Res. Dev. 2013, 17, 169– 174.
12. R. P. Sheridan, et al., Modeling a Crowdsourcing Definition of Molecular Complexity. J. Chem. Inf. Model. 2014, 54, 1604–1616.
13. M. F. Faul, et al., Part 2: Designation and Justification of API Starting Materials: Current Practices across Member Companies of the IQ Consortium. Org. Process Res. Dev. 2014, 18, 594–600.
14. Besides offering simplicity, the GAL’s process complexity model was selected vs. the alternative structural complexity measures due to its inherent ideality-derived consideration for available synthetic methodology.
15. See main article ref. 16: it defines Construction Reactions (CR) as chemical transformations that form skeletal C-C or C-heteroatom bonds. Strategic Redox Reactions (SRR) are construction reactions that directly establish the correct functionality found in the final product, and include asymmetric reductions or oxidations. All other types of non-strategic reactions are considered as Concession Steps (CS), and include functional group interconversions, non-strategic redox reactions, and protecting group manipulations.
16. M. E. Kopach, et al., Process Development and Pilot-Plant Synthesis of (2-Chlorophenyl)[2-(phenylsulfonyl)pyridin-3- yl]methanone. Org. Process Res. Dev. 2010, 14, 1229–1238.
17. M. E. Kopach, M. M. Murray, T. M. Braden, M. E. Kobierski, O. L. Williams, Improved Synthesis of 1-(Azidomethyl)-3,5-bis- (trifluoromethyl)benzene: Development of Batch and Microflow Azide Processes. Org. Process Res. Dev. 2009, 13, 152–160. 18. RCI (Process B) = 1 − ( ) = 0.25. RCI (Process C) = 1 − ( ) = 0.38

//////////green chemistry, drugs

Synthesis of cyclic organic carbonates via catalytic oxidative carboxylation of olefins in flow reactors

 

Synthesis of cyclic organic carbonates via catalytic oxidative carboxylation of olefins in flow reactors

Catal. Sci. Technol., 2017, Advance Article
DOI: 10.1039/C6CY01974A, Paper
Ajay A. Sathe, Anirudh M. K. Nambiar, Robert M. Rioux
The direct catalytic conversion of olefins into cyclic carbonates using peroxide and carbon dioxide is demonstrated using continuous flow reactors.

Synthesis of cyclic organic carbonates via catalytic oxidative carboxylation of olefins in flow reactors

*Corresponding authors
aDepartment of Chemistry, The Pennsylvania State University, University Park, USA
E-mail: rioux@engr.psu.edu
Fax: 814 865 7846
Tel: 814 867 2503
bDepartment of Chemical Engineering, The Pennsylvania State University, University Park, USA
Catal. Sci. Technol., 2017, Advance Article

DOI: 10.1039/C6CY01974A

Methodology for direct catalytic conversion of olefins into cyclic carbonates using peroxide and carbon dioxide under relatively mild conditions is demonstrated. The protocol utilizes packed bed flow reactors in series to couple rhenium catalyzed olefin epoxidation and aluminum catalyzed epoxide carboxylation in a single sequence.

 

 

 

////////Synthesis,  cyclic organic carbonates, catalytic oxidative carboxylation, olefins, flow reactors

Efficient atom and step economic (EASE) synthesis of the “smart drug” Modafinil

Efficient atom and step economic (EASE) synthesis of the “smart drug” Modafinil

Green Chem., 2017, Advance Article
DOI: 10.1039/C6GC02623K, Communication
Shivam Maurya, Dhiraj Yadav, Kemant Pratap, Atul Kumar
We developed a post-sulfoxidation protocol for the synthesis of Modafinil that exhibits improved sustainability credentials, utilizing the recyclable heterogeneous catalyst Nafion-H.

Efficient atom and step economic (EASE) synthesis of the “smart drug” Modafinil

Shivam Maurya,ab   Dhiraj Yadav,a   Kemant Pratapab and  Atul Kumar*ab  
 *Corresponding authors
aMedicinal & Process Chemistry Division, CSIR-Central Drug Research Institute, Sector 10, Jankipuram Extension, Sitapur Road, P.O. Box 173, Lucknow 226031, India
E-mail: dratulsax@gmail.com, atul_kumar@cdri.res.in
bAcademy of Scientific and Innovative Research, New Delhi 110001, India
Green Chem., 2017, Advance Article

DOI: 10.1039/C6GC02623K

Atul Kumar

Atul Kumar

Professor, Academy of Scientific and Innovative Research (AcSIR)/ Senior Principal Scientist at CSIR-CDRI

Central Drug Research Institute

Modafinil (2-[(diphenylmethyl)sulfinyl]acetamide, MOD) is a key psychostimulant drug used for the treatment of narcolepsy and other sleep disorders that has a very low addiction liability. Recently, MOD has been clinically investigated for the treatment of cocaine addiction and used by astronauts in long-term space missions. We have developed a synthetic strategy for “smart drug” Modafinil. An efficient atom and step economic (EASE) synthesis has been carried out by the direct reaction of benzhydrol and 2-mercaptoacetamide using the recyclable heterogeneous catalyst Nafion-H along with post-sulfoxidation. This protocol exhibits improved sustainability credentials. We have also developed a superior pre-sulfoxidation approach for the synthesis of Modafinil.

Modafinil Physical State – White solid; M.p. 158-159ºC,
IR (KBr): 3383, 3314, 3256, 1690, 1 1616, 1494, 1376, 1027, 702 cm-1;
H NMR (CDCl3) δ(ppm): 3.14(d, J=14.3 Hz, 1H); 3.48(d, J=14.3 Hz, 1H); 5.24(s, 1H); 5.88(br s, 1H); 7.09(br s, 1H); 7.29-7.43(m, 7H); 7.43-7.51(m, 3H);
13C NMR (CDCl3) δ(ppm): 52.00, 71.61, 128.80, 128.98, 129.10, 129.58, 129.62, 134.30, 134.74, + 166.46; Molecular formula C15H15NO2S;
ESI-MS (m/z): 274.1 (M+H) .

Dr. Atul Kumar

Senior Principal Scientist

A robust and recyclable polyurea-encapsulated copper(I) chloride for one-pot ring-opening/Huisgen cycloaddition/CO2 capture in water

Green Chem., 2016, 18,6357-6366
DOI: 10.1039/C6GC01956K, Paper
Yun Chen, Wei-Qiang Zhang, Bin-Xun Yu, Yu-Ming Zhao, Zi-Wei Gao, Ya-Jun Jian, Li-Wen Xu
One-pot ring-opening/Huisgen cycloaddition reactions combined with CO2 capture were carried out successfully in the presence of polyurea-encapsulated CuCl.
A robust and recyclable polyurea-encapsulated copper(I) chloride for one-pot ring-opening/Huisgen cycloaddition/CO2 capture in water
Yun Chen,a Wei-Qiang Zhang,a Bin-Xun Yu,a Yu-Ming Zhao,a Zi-Wei Gao,*a Ya-Jun Jiana and Li-Wen Xu*ab
*Corresponding authors
aKey Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education (MOE) and School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi’an 710062, P. R. China
E-mail: liwenxu@hznu.edu.cn, zwgao@snnu.edu.cn
bKey Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, No 1378, Wenyi West Road, Science Park of HZNU, Hangzhou 311121, P. R. China
Green Chem., 2016,18, 6357-6366
DOI: 10.1039/C6GC01956K
Multicomponent ring-opening/Huisgen cycloaddition reactions combined with CO2 capture with a polyurea-encapsulated copper salt as a catalyst that in situ formed from simple CuCl and soluble polyurea during the reaction were carried out successfully for the synthesis of β-hydroxytriazoles under exceptionally mild conditions, in which the polyurea-encapsulated copper(I) chloride proved to be a robust and recyclable catalyst system with high yields as well as excellent chemoselectivity in this reaction.
STR0.JPGstr1STR2.JPGstr3
str0str1str2str3
////////A robust and recyclable,  polyurea-encapsulated, copper(I) chloride,  one-pot,  ring-opening/Huisgen cycloaddition/CO2 capture in water

Metal-free annulation/aerobic oxidative dehydrogenation of cyclohexanones with o-acylanilines: efficient syntheses of acridines

 

Green Chem., 2016, Advance Article
DOI: 10.1039/C6GC02396G, Communication
Gopal Chandru Senadi, Ganesh Kumar Dhandabani, Wan-Ping Hu, Jeh-Jeng Wang
We have identified metal-free reaction conditions for the annulation/aerobic oxidative dehydrogenation of cyclohexanones with o-acylanilines to the corresponding acridine derivatives.
Metal-free annulation/aerobic oxidative dehydrogenation of cyclohexanones with o-acylanilines: efficient syntheses of acridines

Metal-free annulation/aerobic oxidative dehydrogenation of cyclohexanones with o-acylanilines: efficient syntheses of acridines

*Corresponding authors
aDepartment of Medicinal and Applied Chemistry, Kaohsiung Medical University, No. 100, Shiquan 1st Rd, Sanmin District, Kaohsiung City, Taiwan
E-mail: jjwang@kmu.edu.tw
bDepartment of Biotechnology, Kaohsiung Medical University, No. 100, Shiquan 1st Rd, Sanmin District, Kaohsiung City, Taiwan
Green Chem., 2016, Advance Article

DOI: 10.1039/C6GC02396G, http://pubs.rsc.org/en/Content/ArticleLanding/2016/GC/C6GC02396G?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

gopal chandru Senadi
Image result for Gopal Chandru Senadi
link……click

We have identified metal-free reaction conditions for the annulation/aerobic oxidative dehydrogenation of cyclohexanones with o-acylanilines to the corresponding acridine derivatives. The combination of trifluoroacetic acid (TFA), tert-butyl hydroperoxide (TBHP), dimethylsulfoxide (DMSO) and oxygen (O2) converted the cyclohexanone derivatives to an aromatic aryl product in moderate to good yields. The experimental results suggest that this process involves an aza-allyl oxidation intermediate.

Prof. Jeh-Jeng Wang

Professor
Department of Medicinal and Applied Chemistry
Kaohsiung Medical University
Kaohsiung, Taiwan

Lab: N842, Bioorganic chemistry Laboratory
Email: jjwang@kmu.edu.tw
Tel: +886-7-3121101
Fax: 886-7-3125339

Click here to see my official Faculty page at KMU

Click here to email me

Prof. Jeh-Jeng Wang

Education:

B.S., Chemistry, National Chung-Hsing University, Taiwan (1975-1979)

Ph.D., Chemistry, The Ohio State University, USA (1983-1989)

Career:

Teaching Assistant, National Chung-Hsing University, Taiwan (1981-1983)

Postdoctoral fellow, College of Pharmacy, University of Texas, Austin, USA (1989-1991)

Associate Professor, Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Taiwan (1991-2001)

Professor, Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Taiwan (since 2001)

str0 click on imagestr2click on image

 

str0

 

3aa as a pale yellow solid (234 mg, 92%); m.p. 181-182 ° C; IR (neat)max: 1362 cm -1; 1 H NMR (400 MHz, CDCl3) δ 8.31 (d, J = 8.8 Hz, 2H), 7.76 (ddd, J = 8.0, 6.8, 1.6 Hz, 2H), 7.72 (d, J = 8.8 Hz, 2H), 7.66 – 7.56 (m, 3H), 7.49 – 7.41 (m, 4H);

13C NMR (101 MHz, CDCl3) δ 148.66, 147.24, 135.85, 130.37, 129.96, 129.45, 128.40, 128.31, 12

1H NMR

str0 str2

13 c nmr

str0 str1

 

 

//////////Metal-free annulatio, erobic oxidative dehydrogenation, cyclohexanones, o-acylanilines, acridines

Prof. J.J. Wang birthday party – October 21, 2016

 

Department of Medicinal and Applied Chemistry
Kaohsiung Medical University

Image result for Department of Medicinal and Applied Chemistry Kaohsiung Medical University

Image result for Department of Medicinal and Applied Chemistry Kaohsiung Medical University

Asymmetric synthesis of (S)-phenylacetylcarbinol – closing a gap in C–C bond formation

 

Green Chem., 2017, Advance Article
DOI: 10.1039/C6GC01803C, Communication
Torsten Sehl, Saskia Bock, Lisa Marx, Zaira Maugeri, Lydia Walter, Robert Westphal, Constantin Vogel, Ulf Menyes, Martin Erhardt, Michael Muller, Martina Pohl, Dorte Rother
By the combination of biocatalyst design and reaction engineering, the so far not stereoselectively accessible (S)-phenylacetylcarbinol could be enzymatically synthesized with product concentrations >48 g L-1 and an enantiomeric excess up to 97%.
Asymmetric synthesis of (S)-phenylacetylcarbinol – closing a gap in C-C bond formation

Asymmetric synthesis of (S)-phenylacetylcarbinol – closing a gap in C–C bond formation

*Corresponding authors
aInstitute of Bio- and Geosciences, IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, Leo-Brandt-Str. 1, 52425 Jülich, Germany
E-mail: do.rother@fz-juelich.de
bHERBRAND PharmaChemicals GmbH, Brambachstr. 31, 77723 Gegenbach, Germany
cAlbaNova University Center, Royal Institute of Technology – School of Biotechnology, Roslagstull 21, Stockholm, Sweden
d
Institute of Pharmaceutical Sciences, Albert-Ludwigs-University Freiburg, Albertstrasse 25, 79104 Freiburg, Germany
e
Merz Pharma GmbH & Co. KGaA, Am Pharmapark, D-06861 Dessau-Rosslau, Germany
f
Institute of Technical Biochemistry, University of Stuttgart, Allmandring 31, 70569 Stuttgart, Germany
g
TRUMPF GmbH+Co.KG, Ditzingen Johann-Maus-Straße 2, 71254 Ditzingen, Germany
h
Enzymicals AG, Walther-Rathenau-Str 49a, 17489 Greifswald, Germany
Green Chem., 2017, Advance Article

DOI: 10.1039/C6GC01803C

(S)-Phenylacetylcarbinol [(S)-PAC] and its derivatives are valuable intermediates for the synthesis of various active pharmaceutical ingredients (APIs), but their selective synthesis is challenging. As no highly selective enzymes or chemical catalysts were available, we used semi-rational enzyme engineering to tailor a potent biocatalyst to be >97% stereoselective for the synthesis of (S)-PAC. By optimizing the reaction and process used, industrially relevant product concentrations of >48 g L−1 (up to 320 mM) were achieved. In addition, the best enzyme variant gave access to a broad range of ring-substituted (S)-PAC derivatives with high stereoselectivity, especially for meta-substituted products.
str0

///////////Asymmetric synthesis, (S)-phenylacetylcarbinol, C-C bond formation