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
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Palladium-catalyzed coupling of azoles with 1-aryltriazenes via C–H/C–N cleavage

 

Palladium-catalyzed coupling of azoles with 1-aryltriazenes via C–H/C–N cleavage

Wei-Can Daia  and  Zhong-Xia Wang*ab 

*Corresponding authors

aCAS Key Laboratory of Soft Matter Chemistry, Hefei National Laboratory for Physical Sciences at Microscale and Department of Chemistry, University of Science and Technology of China, Hefei, P. R. China
E-mail: zxwang@ustc.edu.cn
Tel: +86 551 63603043

bCollaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, P. R. China

Abstract

In the presence of CuCl and ButOLi, PdCl2/dppe catalyzes the reaction of (benzo)oxazoles or (benzo)thiazoles with 1-aryltriazenes to yield arylated products of (benzo)oxazoles or (benzo)thiazoles. Functional groups including F, Cl, CF3, COOEt, CN, OMe, NMe2, Py, and thienyl groups can be tolerated.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

    

3a (11.2 mg, 38%) were obtained along with unreacted 1 (1.1 mg, 4%).

1H NMR (400 MHz, CS2/CDCl3) δ 8.39 (d, J = 8.0 Hz, 2H), 7.60 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.7 Hz, 2H), 7.41 (d, J = 7.8 Hz, 1H), 7.29 (s, 1H), 7.04 (d, J = 7.8 Hz, 1H), 5.95 (s, 1H), 2.76 (s, 3H), 2.52 (s, 3H);

13C NMR (100 MHz, CS2/CDCl3, all 1C unless indicated) δ 196.06 (C=O), 167.78 (C=O), 152.39, 152.08, 151.38, 150.04, 149.83, 149.22, 148.81, 148.52, 148.26, 147.93, 147.86, 147.73, 147.36, 147.18, 147.14 (2C), 146.91, 146.86, 146.41, 146.40, 145.99 (2C), 145.95, 145.92, 145.53, 145.37, 145.33, 144.82 (2C), 144.80, 144.72, 144.54, 144.42, 144.31, 144.14, 143.84, 143.65, 143.42, 143.31, 143.05, 142.13, 141.93, 141.79, 141.72 (2C), 141.69, 141.55, 141.35, 141.24, 141.10, 140.63, 140.14, 139.93 (aryl C), 138.84, 137.70, 137.54 (aryl C), 137.47, 137.38, 135.44 (aryl C), 133.14 (aryl C), 129.16 (2C, aryl C), 128.72 (2C, aryl C), 128.61 (aryl C), 125.80 (aryl C), 125.42 (aryl C), 115.11 (aryl C), 83.58 (sp3 -C of C60), 69.89 (sp3 -C of C60), 62.42 (sp3 -C of C60), 56.81 (sp3 -C of C60), 26.84, 22.25;

UV-vis (CHCl3) λmax nm (log ε) 251.0 (5.1), 318.5 (4.6), 403.5 (4.0), 440.0 (3.9), 525.5 (3.2), 703.5 (2.5);

FT-IR ν/cm-1 (KBr) 2922, 2860, 1668, 1599, 1499, 1439, 1366, 1304, 1236, 1180, 1086, 1020, 964, 858, 802, 748, 691, 604, 528;

MALDI-TOF MS m/z calcd for C76H16NO2 [M+H]+ 974.1176, found 974.1165.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

Hao-Sheng Lin,a  Yutaka Matsuo,a  Jun-Jie Wanga  and  Guan-Wu Wang*ab 

Author affiliations

Abstract

A regioselective and highly efficient electrochemical method for direct acylation and carboxylation of a [60]fulleroindoline has been developed. By using inexpensive and readily available acyl chlorides and chloroformates, both keto and ester groups can be easily attached onto the fullerene skeleton to afford 1,2,3,16-functionalized [60]fullerene derivatives regioselectively. In addition, a plausible mechanism for the formation of fullerenyl ketones and esters is proposed, and their further transformations under basic and acidic conditions have been investigated.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

    

3a (11.2 mg, 38%) were obtained along with unreacted 1 (1.1 mg, 4%).

1H NMR (400 MHz, CS2/CDCl3) δ 8.39 (d, J = 8.0 Hz, 2H), 7.60 (t, J = 7.4 Hz, 1H), 7.50 (t, J = 7.7 Hz, 2H), 7.41 (d, J = 7.8 Hz, 1H), 7.29 (s, 1H), 7.04 (d, J = 7.8 Hz, 1H), 5.95 (s, 1H), 2.76 (s, 3H), 2.52 (s, 3H);

13C NMR (100 MHz, CS2/CDCl3, all 1C unless indicated) δ 196.06 (C=O), 167.78 (C=O), 152.39, 152.08, 151.38, 150.04, 149.83, 149.22, 148.81, 148.52, 148.26, 147.93, 147.86, 147.73, 147.36, 147.18, 147.14 (2C), 146.91, 146.86, 146.41, 146.40, 145.99 (2C), 145.95, 145.92, 145.53, 145.37, 145.33, 144.82 (2C), 144.80, 144.72, 144.54, 144.42, 144.31, 144.14, 143.84, 143.65, 143.42, 143.31, 143.05, 142.13, 141.93, 141.79, 141.72 (2C), 141.69, 141.55, 141.35, 141.24, 141.10, 140.63, 140.14, 139.93 (aryl C), 138.84, 137.70, 137.54 (aryl C), 137.47, 137.38, 135.44 (aryl C), 133.14 (aryl C), 129.16 (2C, aryl C), 128.72 (2C, aryl C), 128.61 (aryl C), 125.80 (aryl C), 125.42 (aryl C), 115.11 (aryl C), 83.58 (sp3 -C of C60), 69.89 (sp3 -C of C60), 62.42 (sp3 -C of C60), 56.81 (sp3 -C of C60), 26.84, 22.25;

UV-vis (CHCl3) λmax nm (log ε) 251.0 (5.1), 318.5 (4.6), 403.5 (4.0), 440.0 (3.9), 525.5 (3.2), 703.5 (2.5);

FT-IR ν/cm-1 (KBr) 2922, 2860, 1668, 1599, 1499, 1439, 1366, 1304, 1236, 1180, 1086, 1020, 964, 858, 802, 748, 691, 604, 528;

MALDI-TOF MS m/z calcd for C76H16NO2 [M+H]+ 974.1176, found 974.1165.

Regioselective acylation and carboxylation of [60]fulleroindoline via electrochemical synthesis

Hao-Sheng Lin,a  Yutaka Matsuo,a  Jun-Jie Wanga  and  Guan-Wu Wang*ab 

Author affiliations

Abstract

A regioselective and highly efficient electrochemical method for direct acylation and carboxylation of a [60]fulleroindoline has been developed. By using inexpensive and readily available acyl chlorides and chloroformates, both keto and ester groups can be easily attached onto the fullerene skeleton to afford 1,2,3,16-functionalized [60]fullerene derivatives regioselectively. In addition, a plausible mechanism for the formation of fullerenyl ketones and esters is proposed, and their further transformations under basic and acidic conditions have been investigated.

1,5-bis-(2-furanyl)-1,4-pentadien-3-one (FAF)

A catalytic aldol condensation system enables one pot conversion of biomass saccharides to biofuel intermediates

Huixiang Li,ab  Zhanwei Xu,a  Peifang Yana  and  Z. Conrad Zhang*a 

Author affiliations

*Corresponding authors

aState Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
E-mail: zczhang@yahoo.com

bDepartment of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China

Abstract

Producing bio-intermediates from lignocellulosic biomass with minimal process steps has a far-reaching impact on the biofuel industry. We studied the metal chloride catalyzed aldol condensation of furfural with acetone under conditions compatible with the upstream polysaccharide conversions to furfurals. In situ far infrared spectroscopy (FIR) was applied to guide the screening of aldol condensation catalysts based on the distinguishing characteristics of metal chlorides in their coordination chemistries with carbonyl-containing compounds. NiCl2, CoCl2, CrCl3, VCl3, FeCl3, and CuCl2 were selected as the potential catalysts in this study. The FIR results further helped to rationalize the excellent catalytic performance of VCl3 in furfural condensation with acetone, with 94.7% yield of biofuel intermediates (C8, C13) in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) solvent. Remarkably, addition of ethanol facilitated the acetal pathway of the condensation reaction, which dramatically increased the desired product selectivity over the furfural pathway. Most significantly, we demonstrate for the first time that VCl3 catalyzed aldol condensation in acidic medium is fully compatible with upstream polysaccharide hydrolysis to monosaccharide and the subsequent monosaccharide isomerization and dehydration to furfurals. Our preliminary results showed that a 44% yield of biofuel intermediates (C8, C13) can be obtained in one-pot conversion of xylose catalyzed by paired metal chlorides, CrCl2 and VCl3. A number of prior works have shown that the biofuel intermediates derived from the one-pot reaction of this work can be readily hydrogenated to biofuels.

1,5-bis-(2-furanyl)-1,4-pentadien-3-one (FAF)

FAF is a yellow solid.1H NMR (400 MHz, CDCl3, TMS) δ 7.51 – 7.46 (m, 4H), 6.92 (d, J = 15.6 Hz, 2H), 6.69 (d, J = 3.4 Hz, 2H), 6.50 – 6.49 (m, 2H);13C NMR (100 MHz, CDCl3) δ 188.1, 151.6, 144.9, 129.2, 123.2, 115.8, 112.6

2-({3-Methyl-6-[(3R)-3-piperidinylamino]-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl}methyl)-4-fluorobenzonitrile

 

2-({3-Methyl-6-[(3R)-3-piperidinylamino]-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl}methyl)-4-fluorobenzonitrile (8)

Mp: 90 °C decomposed.

 

1H NMR (400 MHz, CD3OD) δ (ppm): 7.85–7.89 (m, 1H), 7.25–7.28 (m, 1H), 6.96–6.99 (m, 1H), 5.37–5.51 (m, 2H), 4.84 (s, 1H), 3.42–3.49 (m, 1H), 3.28 (s, 3H), 3.11–3.15 (m, 1H), 2.89–2.93 (m, 1H), 2.46–2.58 (m, 2H), 1.92–1.95 (m, 1H), 1.48–1.70 (m, 3H).

 

MS (ESI+): m/z, 358.06 ([M + H]+).

Synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions at room temperature

Synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions at room temperature

Green Chem., 2017, Advance Article
DOI: 10.1039/C6GC03494B, Paper

Zheng Fang, Wen-Li Hu, De-Yong Liu, Chu-Yi Yu, Xiang-Guo Hu
A procedure for the synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions has been developed.

An efficient and green procedure for the synthesis of tetrazines has been developed based on an old chemistry reported by Carboni in 1958. Both symmetric and asymmetric 3,6-disubstituted 1,2,4,5-tetrazines can be obtained in moderate to high yields from the corresponding gem-difluoroalkenes under aerobic conditions at room temperature. This work represents a rare example that ambient air is utilized as an oxidant for the synthesis of tetrazines.

Synthesis of tetrazines from gem-difluoroalkenes under aerobic conditions at room temperature

Zheng Fang,^a   Wen-Li Hu,^a   De-Yong Liu,^a  Chu-Yi Yu^ab and   Xiang-Guo Hu*^a  

Hide Affiliations

*

Corresponding authors

^a

National Engineering Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, P. R. China
 E-mail: huxiangg@iccas.ac.cn

^b

Beijing National Laboratory for Molecular Science (BNLMS), CAS Key Laboratory of Molecular Recognition and Function, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China

Green Chem., 2017, Advance Article

DOI: 10.1039/C6GC03494B

http://pubs.rsc.org/en/Content/ArticleLanding/2017/GC/C6GC03494B?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

3,6−bis([1,1'−biphenyl]−4−ylmethyl)−1,2,4,5−tetra zine (3a). (41 mg, 83%). purple solid;

m.p. 200−202°C;

IR(KBr) nmax/cm−1 2924, 2850, 1488, 1451, 1432, 1388, 851, 750;

1 H NMR (400 MHz, CDCl3) 7.55−7.33 (m, 18H), 4.65 (s, 4H).

 13C NMR (100 MHz, CDCl3) δ 169.2, 140.6, 140.4, 134.8, 129.7, 128.8, 127.6, 127.4, 127.1, 40.9;

HRMS (ESI): calcd. for C28H22N4 [M+H]+ 415.19172, found 415.19124.



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