Catalyst- and additive-free Baeyer–Villiger-type oxidation of α-iodocyclopentenones to α-pyrones: using air as the oxidant

An efficient synthetic approach for the synthesis of α-pyrones via Baeyer–Villiger-type oxidation of α-iodocyclopentenones through a catalyst- and additive-free system using air as an environmentally benign oxidant is described. The reaction exhibits excellent functional group compatibility and provides a simple and efficient protocol for the construction of highly functionalized α-pyrones under mild reaction conditions.

Catalyst- and additive-free Baeyer–Villiger-type oxidation of α-iodocyclopentenones to α-pyrones: using air as the oxidant†

Yuanyuan Zhou,^a   Xianxiao Chen,^a   Xiangxiang Ling^a  and  Weidong Rao  *^a  

 Author affiliations

*Corresponding authors

^aJiangsu Key Laboratory of Biomass-based Green Fuels and Chemicals, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
E-mail:weidong@njfu.edu.cn

6-Cyclohexyl-4-phenyl-2H-pyran-2-one (2e)[S3]

Product 2e was obtained as a pale-yellow solid in 68% yield (52 mg) following the general procedure, mp 96-97 °C;

1H NMR (600 MHz, CDCl3) δ 7.58-7.56 (m, 2H), 7.48-7.46 (m, 3H), 6.34 (d, J = 1.3 Hz, 1H), 6.26 (d, J = 0.8 Hz, 1H), 2.48 (tt, J = 11.8, 3.3 Hz, 1H), 2.04-2.01 (m, 2H), 1.87-1.84 (m, 2H), 1.47 (qd, J = 12.5, 3.0 Hz, 2H), 1.39-1.32 (m, 2H), 1.28-1.23 (m, 2H);

13C NMR (150 MHz, CDCl3) δ 169.8, 163.6, 155.6, 136.2, 130.5, 129.1, 126.7, 108.4, 100.9, 42.5, 30.6, 25.9, 25.8

http://www.rsc.org/suppdata/c9/gc/c9gc02725d/c9gc02725d1.pdf

 

/////////https://pubs.rsc.org/en/Content/ArticleLanding/2019/GC/C9GC02725D?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

(R)-3-Chloro-2-hydroxypropyl-4-methoxybenzoate

(R)-3-Chloro-2-hydroxypropyl-4-methoxybenzoate 10

To a stirred solution of (R)-3-chloro-1,2-propanediol (6.61 g, 59.8 mmol) in CH2Cl2 (120 mL) was added imidazole (4.07 g, 59.8 mmol). After the reaction mixture had cooled to 0 °C, p-methoxybenzoyl chloride (10.2 g, 59.8 mmol) in CH2Cl2 (10 mL) was added dropwise via addition funnel. The resulting solution was allowed to warm to room temperature and stirred until complete consumption of starting material by thin layer chromatography (TLC). The mixture was poured into saturated aq NH4Cl (150 mL), and the aqueous layer was extracted with CH2Cl2 (3 × 100 mL). The combined organic extracts were dried (MgSO4), filtered, and concentrated in vacuo to provide chlorohydrin 10as a clear, viscous oil (11.43 g, 78%) that was used without further purification. Rf 0.3 (20% EtOAc/hexanes); ee >99% as determined by chiral SFC (see the Supporting Information); 

1H NMR (500 MHz, CDCl3) δ 8.07−7.94 (m, 2H), 7.00−6.88 (m, 2H), 4.46 (d, J = 5.1 Hz, 2H), 4.22 (dd, J = 10.6, 5.3 Hz, 1H), 3.88 (s, 3H), 3.78−3.64 (m, 2H), 2.73 (d, J = 5.6 Hz, 1H); 

13C NMR (126 MHz, CDCl3) δ 166.7, 163.9, 132.1, 121.9, 114.0, 70.1, 65.7, 55.7, 46.3; 

IR [CH2Cl2 solution] νmax (cm−1) 3454, 2959, 2889, 1713, 1606, 1512, 1259, 1170, 1104, 1028, 848, 770, 697, 614; 

HRMS (ESI-TOF) calcd for C11H13ClO4 (M)+244.0573, found 244.0501.

https://pubs.acs.org/doi/full/10.1021/jo1015807
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https://pubs.acs.org/doi/suppl/10.1021/jo1015807/suppl_file/jo1015807_si_001.pdf

1-(4-fluorophenyl)-6-methyl-2-oxo-1,2-dihydropyridine-3-carboxylic pivalic anhydride

 

1-(4-fluorophenyl)-6-methyl-2-oxo-1,2-dihydropyridine-3-carboxylic pivalic anhydride (10): tan solid,

mp (DSC): onset = 172.4 °C, peak temperature = 173.0 °C;

1H NMR (400 MHz, CD3CN) δ 8.23 (d, J = 7.6 Hz, 1 H), 7.35–7.25 (m, 4 H), 6.36 (d, J = 8.0 Hz, 1 H), 2.02 (s, 3 H), 1.25 (s, 9 H);

13C NMR (100 MHz, CD3CN) 175.9 (1 C), 163.6 (d, 1 C, JCF = 245.4 Hz), 162.9 (1 C ), 161.1 (1 C), 158.2 (1 C), 148.6 (1 C), 135.7 (1 C), 131.0 (d, JCF = 8.7 Hz, 2 C), 117.7 (d, JCF = 23.2 Hz, 2 C), 116.0 (1 C), 107.1 (1 C), 40.4 (1 C), 27.0 (3 C), 22.8 (1 C);

19F NMR (376 MHz, CD3CN) δ -114.2 (m, 1 F);

IR (ATR, cm-1 ) 2966 (w), 2939 (w), 2876 (w), 1789 (vs), 1697 (s), 1682 (vs), 1554 (s), 1509 (vs);

HRMS calcd for C18H18O4NFNa (M+Na+ ) = 354.1112; found 354.1113, δ = 0.3 ppm.

//////////////https://pubs.acs.org/doi/suppl/10.1021/acs.oprd.8b00441

“ALL FOR DRUGS” CATERS TO EDUCATION GLOBALLY, No commercial exploits are done or advertisements added by me. This is a compilation for educational purposes only. P.S. : The views expressed are my personal and in no-way suggest the views of the professional body or the company that I represent

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Nickel-catalyzed regioselective C–H oxygenation: new routes for versatile C–O bond formation

Nickel-catalyzed regioselective C–H oxygenation: new routes for versatile C–O bond formation

Org. Chem. Front., 2019, Advance Article
DOI: 10.1039/C8QO01274A, Research Article

Ze-lin Li, Kang-kang Sun, Chun Cai
Nickel-catalyzed regioselective C–H oxygenation reactions of chelating arenes using iodobenzene diacetate, alcohols, and benzoic acids respectively as attacking reagents have been developed for the first time.
To cite this article before page numbers are assigned, use the DOI form of citation above.

Abstract

Nickel-catalyzed regioselective C–H oxygenation reactions of chelating arenes using iodobenzene diacetate, alcohols, and benzoic acids respectively as attacking reagents have been developed for the first time. Simplicity of operation, broad range of functional group tolerance, use of cheap transition metal nickel, and avoiding extraneous directing groups are the key features, thus providing an important complement to C–H oxygenation reactions and expanding the field of nickel-catalyzed C–H functionalizations. Explorations of mechanistic details are also described.

Nickel-catalyzed regioselective C–H oxygenation: new routes for versatile C–O bond formation

Ze-lin Li,a  Kang-kang Suna  and  Chun Cai*a 

 Author affiliations

*Corresponding authors

aCollege of Chemical Engineering, Nanjing University of Science & Technology, 200 Xiaolingwei, Nanjing, China
E-mail:c.cai@njust.edu.cn

https://pubs.rsc.org/en/Content/ArticleLanding/2019/QO/C8QO01274A#!divAbstract

2-(pyridin-2-yl)phenyl acetate (2a)

Formula: C13H11NO2 Mass: 213

To a mixture of 2-phenylpyridine (77.5 mg, 0.5 mmol) 1a, Ni(acac)2 (25.7 mg, 0.1 mmol, 20 mol %), ligand MePh2P (20.0 mg, 0.1 mmol, 20 mol %), and PhI(OAc)2 (483.2 mg, 0.75 mmol, 1.5 equiv) in a reaction tube was added solvent (CH3CN=2.0 mL). The reaction mixture was stirred at 115 °C for 24 h in air. Following the general procedure, 2a was purified by column chromatography on silica gel (petroleum ether: ethyl acetate = 5:1) as a white solid (80.9 mg, 76%).

1H NMR (500 MHz, Chloroform-d) δ 8.8 – 8.7 (m, 1H), 7.8 – 7.7 (m, 2H), 7.6 (dd, J = 7.9, 1.1 Hz, 1H), 7.5 (td, J = 7.7, 1.7 Hz, 1H), 7.4 (td, J = 7.5, 1.2 Hz, 1H), 7.3 – 7.3 (m, 1H), 7.2 (dd, J = 8.0, 1.2 Hz, 1H), 2.2 (s, 3H).

13C NMR (126 MHz, Chloroform-d) δ 168.4, 154.9, 148.6, 147.1, 135.3, 132.2, 129.8, 128.7, 125.4, 122.6, 122.3, 121.2, 20.0. GC-MS (EI) m/z: 213

 

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Large scale synthesis of chiral (3Z,5Z)-2,7-dihydro-1H-azepine-derived Hamari ligand for general asymmetric synthesis of tailor-made amino acids.

 

(R)-2,2′-bis(bromomethyl)-1,1′-binaphthalene ((R)-17) was prepared in the identical manner and had identical analytical properties to those given here.

¹H NMR (400 MHz, CDCl₃): δ 4.25 (4H, s, 2 × CH₂), 7.07 (2H, dd, J = 8.4, 0.8 Hz, ArH), 7.27 (2H, ddd, J = 8.4, 6.8, 1.2 Hz, ArH), 7.48 (2H, ddd, J = 8.2, 6.8, 1.2 Hz, ArH), 7.74 (2H, d, J = 8.6 Hz, ArH), 7.92 (2H, d, J = 8.2 Hz, ArH), 8.02 (2H, d, J = 8.6 Hz, ArH).

¹³C NMR (100.6 MHz, CDCl₃): δ 32.6 (CH₂), 126.80 (ArCH), 126.82 (ArCH), 126.84 (ArCH), 127.7 (ArCH), 128.0 (ArCH), 129.4 (ArCH), 132.5 (quaternary ArC), 133.3 (quaternary ArC), 134.1 (quaternary ArC), 134.2 (quaternary ArC).

[α]²⁰_D = +173.8° (c = 1.0, CHCl₃).

An advanced process for large scale (500 g) preparation of a (3Z,5Z)-2,7-dihydro-1H-azepine-derived chiral tridentate ligand (Hamari ligand), widely used for asymmetric synthesis of tailor-made α-amino acids via the corresponding glycine Schiff base Ni(II) complex, is disclosed. The process includes amidation, bis-alkylation, and precipitation/purification of the target compound by TFA as a counterion.

Large Scale Synthesis of Chiral (3Z,5Z)-2,7-Dihydro-1H-azepine-Derived Hamari Ligand for General Asymmetric Synthesis of Tailor-Made Amino Acids

Motohiro Takahashi*^† , Hiroki Moriwaki^†, Toshio Miwa^†, Brittanie Hoang^‡, Peng Wang^‡, and Vadim A. Soloshonok*^§∥ 

^† Hamari Chemicals Ltd., 1-4-29 Kunijima, Higashi-Yodogawa-ku, Osaka 533-0024, Japan

^‡ Hamari Chemicals USA, San Diego Research Center, 11494 Sorrento Valley Road, San Diego, California 92121, United States

^§ Department of Organic Chemistry I, Faculty of Chemistry, University of the Basque Country UPV/EHU, Paseo Manuel Lardizábal 3, 20018 San Sebastián, Spain

^∥ IKERBASQUE, Basque Foundation for Science, María Díaz de Haro 3, Plaza Bizkaia, 48013 Bilbao, Spain

Org. Process Res. Dev., Article ASAP

DOI: 10.1021/acs.oprd.8b00406

Publication Date (Web): January 18, 2019

Copyright © 2019 American Chemical Society

*E-mail: motohiro-takahashi@hamari.co.jp., *E-mail: vadym.soloshonok@ehu.es.

This article is part of the Japanese Society for Process Chemistry special issue.

 

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Photo-organocatalytic synthesis of acetals from aldehydes

Abstract

A mild and green photo-organocatalytic protocol for the highly efficient acetalization of aldehydes has been developed. Utilizing thioxanthenone as the photocatalyst and inexpensive household lamps as the light source, a variety of aromatic and aliphatic aldehydes have been converted into acyclic and cyclic acetals in high yields. The reaction mechanism was extensively studied

Photo-organocatalytic synthesis of acetals from aldehydes

 

Nikolaos F. Nikitas,^a  Ierasia Triandafillidi^a  and  Christoforos G. Kokotos*^a 

 Author affiliations

*Corresponding authors

^aLaboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, Athens 15771, Greece
E-mail:ckokotos@chem.uoa.gr

https://pubs.rsc.org/en/Content/ArticleLanding/2019/GC/C8GC03605E?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

(3,3-Dimethoxypropyl)benzene (2a)6
Colorless oil; 95% yield; 1H NMR (200 MHz, CDCl3) δ: 7.33-7.18 (5H, m, ArH), 4.37 (1H, t, J = 5.8 Hz, OCH), 3.33 (6H, s, 2 x OCH3), 2.68 (2H, t, J = 7.6 Hz, CH2), 1.98- 1.87 (2H, m, CH2); 13C NMR (50 MHz, CDCl3) δ: 141.8, 128.4, 125.9, 103.7, 52.8, 34.0, 30.8; MS (ESI) m/z 181 [M+H]+ .
6. Q. Zhou, T. Jia. X.-X. Li, L. Zhou, C.-J. Li, Y. S. Feng, Synth. Commun., 2018, 48, 1068.

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Eco-friendly decarboxylative cyclization in water: practical access to the anti-malarial 4-quinolones

Abstract

An environmentally benign decarboxylative cyclization in water has been developed to synthesize 4-quinolones from readily available isatoic anhydrides and 1,3-dicarbonyl compounds. Isatins are also compatible for the reaction to generate 4-quinolones in the presence of TBHP in DMSO. This protocol provides excellent yields under mild conditions for a broad scope of 4-quinolones, and has good functional group tolerance. Only un-harmful carbon dioxide and water are released in this procedure. Moreover, the newly synthesized products have also been selected for anti-malarial examination against the chloroquine drug-sensitive Plasmodium falciparum 3D7 strain. 3u is found to display excellent anti-malarial activity with an IC₅₀ value of 33 nM.

Eco-friendly decarboxylative cyclization in water: practical access to the anti-malarial 4-quinolones

 

Yue Ma,^a  Yongping Zhu,^a  Dong Zhang,^a  Yuqing Meng,^a  Tian Tang,^a  Kun Wang,^a  Ji Ma,^a  Jigang Wang^a  and  Peng Sun*^a 

 Author affiliations

*Corresponding authors

^aArtermisinin Research Center and Institute of Chinese Meteria Medica, Academy of Chinese Medical Sciences, Beijing, P. R. China
E-mail:psun@icmm.ac.cn

https://pubs.rsc.org/en/Content/ArticleLanding/2019/GC/C8GC03570A?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract
ethyl 2-(4-(benzyloxy)phenyl)-4-oxo-1,4-dihydroquinoline-3-carboxylate (3u) White solid, m.p. 288-289 oC;
1H NMR (600 MHz, DMSO-d6) δ 12.14 (s, 1H), 8.13 (d, J = 8.0 Hz, 1H), 7.72 (ddd, J = 8.4, 7.1, 1.5 Hz, 1H), 7.64 (d, J = 8.3 Hz, 1H), 7.52 (td, J = 8.5, 1.7 Hz, 1H), 7.43 – 7.35 (m, 4H), 7.29 – 7.21 (m, 4H), 7.10 (td, J = 7.5, 0.5 Hz, 1H), 5.17 (s, 2H), 3.91 (q, J = 7.1 Hz, 2H), 2.00 (s, 1H), 0.83 (t, J = 7.1 Hz, 3H) ppm;
13C NMR (150 MHz, DMSO-d6) δ 174.1, 166.2, 156.2, 148.0, 139.8, 137.2, 132.8, 132.0, 130.5, 129.4, 128.7, 128.2, 127.6, 125.5, 125.2, 124.3, 123.6, 120.9, 118.9, 116.4, 115.8, 113.5, 70.2, 60.2, 14.0 ppm;
HRMS (ESI) calcd for [C25H21NO4+H]+ 400.1471, found 400.1463.
 

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A solvent-free catalytic protocol for the Achmatowicz rearrangement

Abstract

Reported here is the development of an environmentally friendly catalytic (KBr/oxone) and solvent-free protocol for the Achmatowicz rearrangement (AchR). Different from all previous methods is that the use of chromatographic alumina (Al₂O₃) allows AchR to proceed smoothly in the absence of any organic solvent and therefore considerably facilitates the subsequent workup and purification with minimal environmental impacts. Importantly, this protocol allows for scaling up (from milligram to gram), recycling of the Al₂O₃, and integrating with other reactions in a one-pot sequential manner.

A solvent-free catalytic protocol for the

Achmatowicz rearrangement

 

Guodong Zhao^a  and  Rongbiao Tong*^ab 

 Author affiliations

*Corresponding authors

^aDepartment of Chemistry, The Hong Kong University of Science and Technology, Clearwater Bay, Kowloon, China
E-mail: rtong@ust.hk
Fax: +(852)23581594
Tel: +(852) 23587357

^bHKUST Shenzhen Research Institute, Shenzhen 518057, China

https://pubs.rsc.org/en/Content/ArticleLanding/2019/GC/C8GC03030H?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FGC+%28RSC+-+Green+Chem.+latest+articles%29#!divAbstract

1n: colorless oil, 0.33 g, 73% yield for 2 steps.

1H-NMR (400 MHz, DMSO) δ: 7.59–7.58 (m, 1H), 7.45 (s, 2H), 6.40 (dd, J = 3.2, 1.8 Hz, 1H), 6.29 (d, J = 3.2 Hz, 1H), 5.49 (s, 1H), 4.74–4.60 (m, 1H), 4.18–4.07 (m, 2H), 2.09–2.04 (m, 2H).

13C-NMR (100 MHz, DMSO) δ: 157.6, 142.4, 110.7, 106.1, 66.5, 62.8, 35.2. IR (KBr) 3282.9, 2928.7, 1627.4, 1562.5, 1353.8, 1174.6, 1074.0, 999.7, 918.4, 742.8 cm-1 ;

HRMS (CI+ ) (m/z) calcd. for C7H11NO5S [M]+ 221.0352; found 221.0354.

  

2n (EtOAc/hexane = 3:1):colorless oil (dr 7:3), 46 mg, 97%.

1H-NMR (400 MHz, DMSO) δ: 7.48–7.47 (m, 2H), 7.34–7.02 (m, 2H), 6.12–6.03 (m, 1H), 5.61–5.48 (m, 1H), 4.60 (dd, J = 8.3, 4.1 Hz, 0.7H), 4.28 (ddd, J = 8.8, 4.0, 1.3 Hz, 0.3H), 4.20–4.11 (m, 2H), 2.27–2.20 (m, 1H), 1.97–1.86 (m, 1H).

13C-NMR (100 MHz, DMSO) δ: 196.7, 196.5, 151.9, 148.3, 127.7, 126.0, 90.9, 87.2, 74.6, 70.1, 65.8, 65.8, 30.3, 29.6. IR (KBr) 3370.4, 2987.0, 1689.5, 1364.3, 1268.0, 1178.4, 1023.3, 928.3, 755.1 cm-1 ;

HRMS (CI+ ) (m/z) calcd. for C7H11NO6S [M]+ 237.0302; found 237.0315.

 

////////////////Achmatowicz rearrangement

(1S,4R)-2-(4-Methoxybenzoyl)bicyclo[2.2.2]octa-2,5-diene

 

(1S,4R)-2-(4-Methoxybenzoyl)bicyclo[2.2.2]octa-2,5-diene (3a) Yellow liquid (25.2 mg, 95% yield):

1H NMR (300 MHz, CDCl3)   1.39 (s, 4H, alkyl), 3.77-3.80 (m, 1H, alkyl), 3.85 (s, 3H, OMe), 4.36 (d, J = 5.4 Hz, 1H, alkyl), 6.36 (dd, J = 6.0, 6.0 Hz, 1H, vinyl), 6.46 (dd, J = 6.0, 6.0 Hz, 1H, vinyl), 6.88-6.91 (m, 3H, vinyl + arom.), 7.67 (d, J = 8.3 Hz, 2H, arom.);

13C{1H} NMR (75 MHz, CDCl3)  = 24.7, 24.8, 37.1, 38.2, 55.4, 113.3, 130.8, 131.5, 133.2, 135.1, 146.5, 147.7, 162.6, 192.3;

HRMS (ESI-TOF) m/z calculated for C16H16NaO2 [M+Na]+ 263.1048, found 263.1036;

FT-IR (neat, cm-1 ) 1033, 1174, 1255, 1354, 1600, 1637, 1730, 2870, 2957, 3054.

Optical Rotation: []D 26 +39.9 (c 2.52, CHCl3) for an enantiomerically enriched sample of 94% ee.

HPLC analysis (column, CHIRALPAK AD-3, hexane/2-propanol = 98/2, flow rate 1.0 mL/min, 20 C, detection UV 250 nm light); tR of major-isomer 20.7

Org. Lett., 2018, 20 (23), pp 7353–7357

DOI: 10.1021/acs.orglett.8b02263

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(1S,4R)-2-(4-Methoxybenzoyl)bicyclo[2.2.2]octa-2,5-diene

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ANTHONY MELVIN CRASTO

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