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

/////////