Asymmetric synthesis of ent-fragransin C1

http://pubs.rsc.org/en/Content/ArticleLanding/2017/OB/C7OB00749C?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FOB+%28RSC+-+Org.+Biomol.+Chem.+latest+articles%29#!divAbstract

Asymmetric synthesis of ent-fragransin C1

Org. Biomol. Chem., 2017, Advance Article
DOI: 10.1039/C7OB00749C, Paper

Santikorn Chaimanee, Manat Pohmakotr, Chutima Kuhakarn, Vichai Reutrakul, Darunee Soorukram
The first asymmetric synthesis of ent-fragransin C1 bearing 2,3-anti-3,4-syn-4,5-anti stereochemistries is reported.

Asymmetric synthesis of ent-fragransin C1

Santikorn Chaimanee,a  Manat Pohmakotr,a  Chutima Kuhakarn,a  Vichai Reutrakula  and  Darunee Soorukram*a 

*Corresponding authors

aDepartment of Chemistry and Center of Excellence for Innovation in Chemistry (PERCH-CIC), Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand
E-mail: darunee.soo@mahidol.ac.th
Fax: +662 354 7151
Tel: +662201 5148

Abstract

The first asymmetric synthesis of ent-fragransin C1 was reported. The key step involves an intramolecular C–O bond formation (furan ring formation) via chemoselective generation of the benzylic carbocation leading to the 2,3-anti-3,4-syn-4,5-anti-tetrahydrofuran moiety as a single diastereomer in good yield. Our synthesis confirms that ent-fragransin C1 possesses 2R,3R,4S,5S configurations.

4-[(2R,3R,4S,5S)-5-(4-Hydroxy-3-methoxyphenyl)-3,4- dimethyltetrahydrofuran-2-yl]-2,6-dimethoxyphenol (ent-1). A flame-dried.......................... in vacuo, the crude product was purified by column chromatography (60% EtOAc in hexanes) to afford ent-1 as a sticky brownish oil (15.3 mg, 99% yield) as a single diastereomer (400 MHz 1 H NMR analysis). Rf 0.18 (40% EtOAc in hexanes);

[α]27 D -6.97 (c 0.60, CHCl3 ) (lit. [α]D +3.8 (c 0.60, CHCl3 ); 4a

UV (MeOH) λmax (log ε) 208 (0.85), 233 (0.24), 279 (0.07) nm; CD (MeOH) 226 (Δε 2.23), 250 (Δε +0.12).

1 H NMR (400 MHz, acetone-d6 ): δ 7.51 (s, 1H, OH), 7.12 (s, 1H, OH), 7.10 (d, J = 1.8 Hz, 1H, ArH), 6.92 (d, J = 8.1, 1.8 Hz, 1H, ArH), 6.82 (d, J = 8.1 Hz, 1H, ArH), 6.77 (s, 2H, 2  ArH), 4.43 (d, J = 5.4 Hz, 1H, 2  xCH), 3.86 (s, 3H, OCH3 ), 3.83 (s, 6H, 2  xOCH3 ), 2.202.45 (m, 2H, 2  xCH), 1.03 (d, J = 6.7 Hz, 3H, CH3 ), 1.00 (d, J = 6.7 Hz, 3H, CH3 ).

13C NMR (100 MHz, acetone-d6 ): δ 149.0 (2  C), 148.7 (C), 147.3 (C), 136.6 (C), 135.5 (C), 134.7 (C), 120.4 (CH), 115.9 (CH), 111.2 (CH), 105.1 (2  CH), 88.7 (CH), 88.4 (CH), 57.0 (2  CH3 ), 56.6 (CH3 ), 46.1 (CH), 45.7 (CH), 13.7 (CH3 ), 13.5 (CH3 ).

IR (CHCl3 ): νmax 3542s, 1616m, 1517s, 1465s, 1117s cm−1 .

MS (ISCID): m/z (%) relative intensity 397 [(M + Na)+ , 100], 357 (1).

HRMS (ESI-TOF) calcd for C21H26O6Na [M + Na]+ : 397.1627, found: 397.1622.

4 (a) M. Hattori, S. Hada, Y. Kawata, Y. Tezuka, T. Kikuchi and T. Namba, Chem. Pharm. Bull., 1987, 35, 3315; (

Darunee Soorukram

Assistant Professor

Darunee Soorukram

Education

• B.Sc. (Chemistry), Khon Kean University, Khon Kean, Thailand
• M.Sc. (Organic Chemistry), Mahidol University, Bangkok, Thailand
• Ph.D., Ludwig-Maximilians-University, Munich, Germany

Name : Darunee Soorukram     ดรุณี สู้รักรัมย์ Title : Assistant Professor Dr. Education : Ph.D. (Ludwig-Maximilians-University), Germany     Expertise : -     Contact Address : Department : Chemistry   Room : C418B   Phone : (662) 201 5148     E-Mail : darunee.soo@mahidol.ac.th         More Information : CV from Dept. Chemistry Website       รางวัลวิทยานิพนธ์ ระดับดีเยี่ยม (สาขาวิทยาศาสตร์เคมีและเภสัช) จากสภาวิจัยแห่งชาติ   Most Recent Articles from Scopus : Soorukram D (Author ID: 6506453550) O -Iodoxybenzoic Acid (IBX)-Iodine Mediated One-Pot Deacylative Sulfonylation of 1,3-Dicarbonyl Compounds: A Synthesis of β-Carbonyl Sulfones  2017; Synthesis (Germany); Katrun, P. | Songsichan, T. | Soorukram, D. | Pohmakotr, M. | Reutrakul, V. |... Cytotoxic lanostanes from fruits of Garcinia wallichii Choisy (Guttiferae)  2016; Bioorganic and Medicinal Chemistry Letters; Hongthong, S. | Meesin, J. | Pailee, P. | Soorukram, D. | Kongsaeree, P. |... Iodine-catalyzed Sulfonylation of Arylacetylenic Acids and Arylacetylenes with Sodium Sulfinates: Synthesis of Arylacetylenic Sulfones  (Cited 11 time(s)) 2016; Journal of Organic Chemistry; Meesin, J. | Katrun, P. | Pareseecharoen, C. | Pohmakotr, M. | Reutrakul, V. |... Decarboxylative sulfonylation of arylpropiolic acids with sulfinic acids: synthesis of (E)-vinyl sulfones  (Cited 1 time(s)) 2016; Tetrahedron; Meesin, J. | Katrun, P. | Reutrakul, V. | Pohmakotr, M. | Soorukram, D. |... Nitration-Oximization of Styrene Derivatives with tert-Butyl Nitrite: Synthesis of α-Nitrooximes  2016; Chinese Journal of Chemistry; Chumnanvej, N. | Katrun, P. | Pohmakotr, M. | Reutrakul, V. | Soorukram, D. |... Intramolecular Conjugate Ene Reaction of γ-Difluoromethyl- and γ-Trifluoromethyl-α,β-Unsaturated γ-Butyrolactones  2015; Journal of Organic Chemistry; Srimontree, W. | Masusai, C. | Soorukram, D. | Kuhakarn, C. | Reutrakul, V. |... Stereoselective Synthesis of 1-Fluoro-exo,exo-2,6-diaryl-3,7-dioxabicyclo[3.3.0]octanes: Synthesis of (±)-1-Fluoromembrine  (Cited 1 time(s)) 2015; Journal of Organic Chemistry; Punirun, T. | Soorukram, D. | Kuhakarn, C. | Reutrakul, V. | Pohmakotr, M. Synthesis of γ-difluoromethyl α,β-unsaturated γ-butyrolactones using PhSCF<inf>2</inf>SiMe<inf>3</inf> as a difluoromethylating agent  (Cited 3 time(s)) 2015; European Journal of Organic Chemistry; Issaree, A. | Masusai, C. | Soorukram, D. | Kuhakarn, C. | Reutrakul, V. |... Silver-mediated decarboxylative fluorination of paraconic acids: A direct entry to β-fluorinated γ-butyrolactones  (Cited 10 time(s)) 2015; European Journal of Organic Chemistry; Phae-Nok, S. | Soorukram, D. | Kuhakarn, C. | Reutrakul, V. | Pohmakotr, M. PhI(OAc)<inf>2</inf> mediated decarboxylative sulfonylation of β-aryl-α,β-unsaturated carboxylic acids: A synthesis of (E)-vinyl sulfones  (Cited 18 time(s)) 2015; Organic and Biomolecular Chemistry; Katrun, P. | Hlekhlai, S. | Meesin, J. | Pohmakotr, M. | Reutrakul, V. |... Access all results for your search in Scopus

Contact

Phone: +66.(0).2.201.5148

LAB Tel: +66.(0).2.201.5149
Fax: +66.(0).2.354.7151
E-mail:darunee.soo@mahidol.ac.th

Address:
Room C418B
Department of Chemistry,
Faculty of Science, Mahidol University,
Rama 6 Road, Ratchthewee
Bangkok 10400 Thailand

/////////

One-step asymmetric synthesis of (R)- and (S)-rasagiline by reductive amination applying imine reductases

One-step asymmetric synthesis of (R)- and (S)-rasagiline by reductive amination applying imine reductases

Green Chem., 2017, Advance Article
DOI: 10.1039/C6GC03023H, Communication

P. Matzel, M. Gand, M. Hohne
Imine reductases (IREDs) show great potential as catalysts for reductive amination of ketones to produce chiral secondary amines.

One-step asymmetric synthesis of (R)- and (S)-rasagiline by reductive amination applying imine reductases

Imine reductases (IREDs) show great potential as catalysts for reductive amination of ketones to produce chiral secondary amines. In this work, we explored this potential and synthesized the pharmaceutically relevant (R)-rasagiline in high yields (up to 81%) and good enantiomeric excess (up to 90% ee) from the ketone precursor. This one-step approach in aqueous medium represents the shortest synthesis route from achiral starting materials. Furthermore, we demonstrate for the first time that tertiary amines also can be accessed by this route, which provides new opportunities for eco-friendly enzymatic asymmetric syntheses of these important molecules.

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C6GC03023H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

One-step asymmetric synthesis of (R)- and (S)-rasagiline by reductive amination applying imine reductases

P. Matzel,^a   M. Gand^b and   M. Höhne*^a  

*Corresponding authors

^aInstitute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
E-mail: Matthias.Hoehne@uni-greifswald.de

^bBiocenter Klein Flottbek, University of Hamburg, Ohnhorststr. 18, 22609 Hamburg, Germany

Green Chem., 2017, Advance Article

DOI: 10.1039/C6GC03023H

    

 

////////////One-step, asymmetric synthesis,  (R)- ,  (S)-rasagiline,  reductive amination,  imine reductases