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1. Copper-Catalyzed C4-H Regioselective Phosphorylation/Trifluoromethylation of Free 1-Naphthylamines

Author:
Jing, Chunfeng; Chen, Xiaolan; Sun, Kai; Yang, Yongkang; Chen, Tong; Liu, Yan; Qu, Lingbo; Zhao, Yufen; Yu, Bing
Source:
Organic letters 2019 v.21 no.2 pp. 486-489
ISSN:
1523-7052
Subject:
regioselectivity,   etc   ; chemical structure; copper; dimethyl sulfoxide; oxides; phosphorylation;     Show all 6 Subjects
Abstract:
... A novel and facile copper-catalyzed synthetic methodology was developed to access a large variety of 4-phosphoryl-substituted 1-naphthylamines by reacting various 1-naphthylamines with different diarylphosphine oxides in the presence of Cu(OAc)₂ and Ag₂CO₃ in one pot under mild reaction conditions. This copper-catalyzed synthetic system was also suitable for being employed to synthesize 4-trifluor ...
DOI:
10.1021/acs.orglett.8b03768

2. Synthesis of triphenylene derivatives by Pd-catalyzed Suzuki coupling/intramolecular CH activation between arylboronic acids and dibromobiphenyls

Author:
Tu, Jingxuan; Li, Gaoqiang; Zhao, Xiaoqian; Xu, Feng
Source:
Tetrahedron letters 2019 v.60 no.1 pp. 44-47
ISSN:
0040-4039
Subject:
regioselectivity,   etc   ; Suzuki reaction; catalytic activity; chemical structure; organic compounds; palladium;     Show all 6 Subjects
Abstract:
... An efficient and regioselective synthesis of functionalized triphenylenes via palladium-catalyzed Suzuki-Miyaura coupling and subsequent intramolecular CH activation between arylboronic acids and dibromobiphenyls was developed. This methodology showed excellent atomic economy and regiospecificity as well as synthetic feasibility of unsymmetrical triphenylenes. ...
DOI:
10.1016/j.tetlet.2018.11.052

3. Total Synthesis of Sekothrixide Strategically Utilizing Regioselective Coupling of TMS-Protected Epoxy sec-Alcohol with Gilman Reagent

Author:
Katsumi, Daisuke; Nakasone, Kazuki; Terayama, Naoki; Yasui, Eiko; Mizukami, Megumi; Miyashita, Masaaki; Nagumo, Shinji
Source:
Journal of organic chemistry 2019 v.84 no.3 pp. 1553-1562
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; chemical reactions; chemical structure; epoxides; organic chemistry;     Show all 5 Subjects
Abstract:
... A new efficient synthesis of sekothrixide was established on the basis of our developed regioselective coupling of epoxy sec-alcohol with Gilman reagent guided by a TMS group. The new synthetic route allowed an overall yield of 6.3% (26 steps) from optically active 3-silyloxy-2-methylaldehyde. ...
DOI:
10.1021/acs.joc.8b03006

4. Regioselective and Enantioselective Cu(II)-Catalyzed 1,4-Conjugate Addition of Diethylzinc Reagent to Nitrodienes

Author:
Rexiti, Rukeya; Zhang, Zhen-Guo; Lu, Jian; Sha, Feng; Wu, Xin-Yan
Source:
Journal of organic chemistry 2019 v.84 no.3 pp. 1330-1338
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; chemical reactions; chemical structure; copper; enantioselectivity; ligands; organic chemistry; organic compounds;     Show all 8 Subjects
Abstract:
... The regioselective and enantioselective Cu(II)-catalyzed 1,4-conjugate addition of diethylzinc reagent to nitrodienes is described. With 0.25 mol % of Cu(OAc)₂ and chiral amidophosphine ligand L3, the 1,4-addition products were produced with a complete regioselectivity, high yields (81–98%), and excellent enantioselectivities (87–97% ee) in a short reaction time. ...
DOI:
10.1021/acs.joc.8b02798

5. Metal-Free Regioselective Monocyanation of Hydroxy-, Alkoxy-, and Benzyloxyarenes by Potassium Thiocyanate and Silica Sulfuric Acid as a Cyanating Agent

Author:
Sardarian, Ali Reza; Dindarloo Inaloo, Iman; Modarresi-Alam, Ali Reza; Kleinpeter, Erich; Schilde, Uwe
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 1748-1756
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; byproducts; chemical reactions; chemical structure; organic chemistry; organic compounds; potassium thiocyanate; silica; sulfuric acid; toxicity;     Show all 10 Subjects
Abstract:
... A novel and efficient metal- and solvent-free regioselective para-C–H cyanation of hydroxy-, alkoxy-, and benzyloxyarene derivatives has been introduced, using nontoxic potassium thiocyanate as a cyanating reagent in the presence of silica sulfuric acid (SSA). The desired products are obtained in good to high yields without any toxic byproducts. ...
DOI:
10.1021/acs.joc.8b02191

6. Transition-Metal-Free Regioselective One-Pot Synthesis of Aryl Sulfones from Sodium Sulfinates via Quinone Imine Ketal

Author:
Halder, Priyanka; Humne, Vivek T.; Mhaske, Santosh B.
Source:
Journal of organic chemistry 2019 v.84 no.3 pp. 1372-1378
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; chemical reactions; chemical structure; imines; organic chemistry; quinones; salts; synthesis;     Show all 8 Subjects
Abstract:
... A novel, efficient, and regioselective transition-metal-free one-pot synthesis of aryl sulfones via the reactive quinone imine ketal intermediate is demonstrated using easily accessible bench-stable sulfinate salts. A broad range of functionality on p-anisidine substrates as well as sulfinate salts was tolerated under mild reaction conditions to provide the corresponding aryl sulfones in good to e ...
DOI:
10.1021/acs.joc.8b02835

7. Triple-Bond Insertion Triggers Highly Regioselective 1,4-Aminomethylamination of 1,3-Enynes with Aminals Enabled by Pd-Catalyzed C–N Bond Activation

Author:
Zhang, Yanchen; Yu, Bangkui; Gao, Binjian; Zhang, Tianze; Huang, Hanmin
Source:
Organic letters 2019 v.21 no.2 pp. 535-539
ISSN:
1523-7052
Subject:
regioselectivity,   etc   ; catalysts; catalytic activity; chemical bonding; chemical reactions; chemical structure; organic compounds; palladium;     Show all 8 Subjects
Abstract:
... A highly chemo- and regioselective 1,4-aminomethylamination of simple enynes with aminals to allenic 1,5-diamines by taking advantage of C–N bond activation has been reported. The reaction proceeds under mild reaction conditions and can be performed under lower catalyst loading (0.1 mol %) with high efficiency and broad substrate scope. ...
DOI:
10.1021/acs.orglett.8b03847

8. Copper-Catalyzed Intramolecular Chalcogenoamination of Enynyl Azides: Synthesis of 5-Selenyl/Sulfenyl Nicotinates

Author:
Reddy, Chada Raji; Ranjan, Ravi; Prajapti, Santosh Kumar
Source:
Organic letters 2019 v.21 no.3 pp. 623-626
ISSN:
1523-7052
Subject:
regioselectivity,   etc   ; alkynes; azides; chemical reactions; chemical structure; oxides;     Show all 6 Subjects
Abstract:
... A novel methodology for the synthesis of 5-selenyl/sulfenyl nicotinates involving copper-catalyzed organochalcogenyl aza-annulation of enynyl azide with diorganyl-dichalcogenides has been described. This method offers difunctionalization of alkynes via regioselective intramolecular chalcogenoamination in one pot to provide substituted 5-chalcogenyl nicotinates in good to excellent yields. The resu ...
DOI:
10.1021/acs.orglett.8b03695

9. Cu-catalyzed direct ortho-chlorination/-oxygenation of aryls: Switching of oxidant, control the diversity of products

Author:
Botla, Vinayak; Akudari, Ashok; Malapaka, Chandrasekharam
Source:
Tetrahedron letters 2019 v.60 no.2 pp. 115-119
ISSN:
0040-4039
Subject:
regioselectivity,   etc   ; chemical reactions; chemical structure; copper; ethylene dichloride; oxidants; pyridines;     Show all 7 Subjects
Abstract:
... Highly regioselective copper catalyzed ortho-chlorination of aryl pyridines was achieved with TBHP as oxidant and 1,2-dichloroethane as chlorinating agent for the first time. Switching the oxidant from TBHP to benzoyl peroxide under identical reaction conditions effects ortho-oxygenation. ...
DOI:
10.1016/j.tetlet.2018.11.071

10. Ligand-Free Iron-Catalyzed C–F Amination of Diarylamines: A One-Pot Regioselective Synthesis of Diaryl Dihydrophenazines

Author:
Aoki, Yuma; O’Brien, Harry M.; Kawasaki, Hiroto; Takaya, Hikaru; Nakamura, Masaharu
Source:
Organic letters 2019 v.21 no.2 pp. 461-464
ISSN:
1523-7052
Subject:
regioselectivity,   etc   ; amination; chemical structure; cyclization reactions; ferrous chloride; fluorine; iron; magnesium; organic compounds; synthesis;     Show all 10 Subjects
Abstract:
... A one-pot synthesis of various 5,10-diaryl-5,10-dihydrophenazines (DADHPs) from diarylamines has been achieved by using an iron-catalyzed C–F amination. Homodimerization of magnesium diarylamides, followed by defluorinative intramolecular cyclization (double ortho C–F amination) in the presence of catalytic FeCl₂ and stoichiometric 1,2-dibromoethane, affords the corresponding DADHPs with complete ...
DOI:
10.1021/acs.orglett.8b03702

11. Copper-Catalyzed Radical C–C Bond Cleavage and [4+1] Annulation Cascade of Cycloketone Oxime Esters with Enaminothiones

Author:
He, Yuan; Lou, Jiang; Wu, Kaikai; Wang, Hongmei; Yu, Zhengkun
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 2178-2190
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; catalytic activity; chemical bonding; chemical reactions; chemical structure; cleavage (chemistry); copper; esters; organic chemistry; thermodynamics;     Show all 10 Subjects
Abstract:
... Carbon–carbon bond formation is among the most important reactions in organic synthesis. Reconstruction of a carbon–carbon bond through ring-opening C–C bond cleavage of a strained carbocycle usually occurs via a thermodynamically preferable pathway. However, carbon–carbon bond formation through thermodynamically less favorable C–C bond cleavage has seldom been documented. Herein, we disclose an u ...
DOI:
10.1021/acs.joc.8b03175

12. Reagent-Controlled Reversal of Regioselectivity in Nucleophilic Fluorination of Spiro-epoxyoxindole: Synthesis of 3-Fluoro-3-hydroxymethyloxindole and 3-Aryl-3-fluoromethyloxindole

Author:
Hajra, Saumen; Roy, Sayan; Maity, Subrata; Chatterjee, Sandip
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 2252-2260
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; Lewis bases; chemical reactions; chemical structure; fluorides; organic chemistry; organic compounds;     Show all 7 Subjects
Abstract:
... A convenient and metal/catalyst-free approach for the reversal of regioselectivity in nucleophilic fluorination of a wide range of spiro-epoxyoxindoles has been reported simply by altering the nucleophilic fluoride reagents. Py·(HF)ₓ-mediated fluorination at the tertiary sp³-C center of spiro-epoxyoxindole furnishes 3-fluoro-3-hydroxymethyloxindoles, whereas TBAF-mediated fluoride addition at the ...
DOI:
10.1021/acs.joc.9b00059

13. Formal [3 + 3] Cycloaddition Reactions between Electron-Deficient Cyclopropenes and Hydrazones: A Route to Alkyl 1,4,5,6-Tetrahydropyridazine-3-carboxylates

Author:
Huo, Hengrui; A, Runa; Gong, Yuefa
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 2093-2101
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; chemical structure; cycloaddition reactions; hydrazones; niacin; organic chemistry;     Show all 6 Subjects
Abstract:
... A formal [3 + 3] cycloaddition reaction between alkyl 2-aroyl-1-chlorocyclopropanecarboxylates 1 and common hydrazones 2 was developed. This process readily proceeded in diastereo- and regioselective fashion and gave alkyl 1,4,5,6-tetrahydropyridazine-3-carboxylates in high yields under mild basic conditions. Treatment of the annulation products with DDQ leads to the formation of functionalized py ...
DOI:
10.1021/acs.joc.8b03105

14. Ru-Catalyzed Regioselective Cascade Annulation of Acrylamides with 2-Alkynoates for the Synthesis of Various 6-Oxo Nicotinic Acid Esters

Author:
Garad, Dnyaneshwar N.; Mhaske, Santosh B.
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 1863-1870
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; acrylamides; chemical reactions; chemical structure; copper; esters; niacin; organic chemistry; oxidants; silver;     Show all 10 Subjects
Abstract:
... Ru-catalyzed regioselective cascade annulation of acrylamides with 2-alkynoates via aza-Michael/C–H activation sequence for the synthesis of various 6-oxo nicotinic acid esters is described. The regioselectivity of the protocol has been confirmed by performing silver mediated protodecarboxylation of the corresponding 6-oxo nicotinic acid to furnish 2-pyridone. The developed protocol is copper or s ...
DOI:
10.1021/acs.joc.8b02783

15. Catalytic Formal Benzylic C–H Bond Functionalization of 2,5-Dialkylfuran Derivatives with Ferrocenyl Alcohols as Alkylation Reagents

Author:
Ren, Didi; Xu, Lubin; Wang, Liang; Li, Shuai-Shuai
Source:
Organic letters 2019 v.21 no.3 pp. 627-631
ISSN:
1523-7052
Subject:
regioselectivity,   etc   ; alcohols; alkylation; ambient temperature; carbon-hydrogen bond activation; chemical bonding; chemical structure; heterocyclic compounds;     Show all 8 Subjects
Abstract:
... The inert benzylic C–H bond of π-electron-rich heteroaromatic 2,5-dialkylfuran derivatives was conveniently functionalized with ferrocenyl alcohols as alkylation reagents under catalytic acidic conditions at room temperature, which features chemo- and regiospecificity, mild and metallic catalyst-free conditions, and environmental benignity. ...
DOI:
10.1021/acs.orglett.8b03701

16. Selective Synthesis of (+)-Dysoline

Author:
Coffin, Aaron; Ready, Joseph M.
Source:
Organic letters 2019 v.21 no.3 pp. 648-651
ISSN:
1523-7052
Subject:
regioselectivity,   etc   ; Dysoxylum gotadhora; alkaloids; chemical reactions; chemical structure; cytotoxicity; enantioselectivity; fibrosarcoma; inhibitory concentration 50; piperidines; stereochemistry;     Show all 11 Subjects
Abstract:
... Dysoline, a novel chromone alkaloid isolated from Dysoxylum binectariferum, was reported to have selective cytotoxicity for HT1080 fibrosarcoma cells (IC₅₀ of 0.21 μM). Given the scarcity of natural material, a concise synthesis of (+)-dysoline was developed, allowing for further biological evaluation. An enantioselective nucleophile-catalyzed aldol lactonization formed the piperidine ring with co ...
DOI:
10.1021/acs.orglett.8b03777

17. Pt-Catalyzed Hydrosilylation of 1,3-Diynes with Triorganosilanes: Regio- and Stereoselective Synthesis of Mono- or Bis-silylated Adducts

Author:
Walkowiak, Jędrzej; Salamon, Katarzyna; Franczyk, Adrian; Stefanowska, Kinga; Szyling, Jakub; Kownacki, Ireneusz
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 2358-2365
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; catalysts; chemical reactions; chemical structure; organic chemistry; organic compounds; platinum; stereoselective synthesis;     Show all 8 Subjects
Abstract:
... An efficient method has been successfully developed for the functionalization of various 1,3-diynes by the hydrosilylation reaction with triethyl- or triphenylsilane catalyzed by Pt catalysts (Pt₂(dvs)₃, PtO₂, or Pt(PPh₃)₄). Comprehensive optimization studies were performed for the first time to find suitable process conditions for the stereo- and regioselective formation of mono- or bis-silylated ...
DOI:
10.1021/acs.joc.8b03143

18. Mechanism and Regioselectivity of an Unsymmetrical Hexadehydro-Diels–Alder (HDDA) Reaction

Author:
Chen, Maggie; He, Cyndi Qixin; Houk, K. N.
Source:
Journal of organic chemistry 2019 v.84 no.4 pp. 1959-1963
ISSN:
1520-6904
Subject:
regioselectivity,   etc   ; amines; chemical reactions; chemical structure; density functional theory; organic chemistry; phenols;     Show all 7 Subjects
Abstract:
... Hoye reported intramolecular hexadehydro-Diels–Alder (HDDA) reactions to generate arynes that functionalize natural product phenols and amines. In their studies, Hoye found that unsymmetrical tetraynes selectively form a single aryne. We report density functional theory (DFT) calculations that reveal the factors controlling the regioselectivity. ...
DOI:
10.1021/acs.joc.8b02865

19. An efficient synthesis of 2-isoxazolines from α-haloketone oximes and dimethyl sulfonium salts

Author:
Zhao, Sen; Wang, Hang; Sun, Shaofa; Guo, Haibing; Chen, Zhiyu; Wang, Jian; Wang, Lu; Liang, Steven; Wang, Gangqiang
Source:
Tetrahedron letters 2019 v.60 no.4 pp. 382-385
ISSN:
0040-4039
Subject:
regioselectivity,   etc   ; chemical structure; cycloaddition reactions; oximes; salts; sulfur;     Show all 6 Subjects
Abstract:
... 2-Isoxazolines were synthesized efficiently from a formal [4+1] cycloaddition of nitrosoalkenes and sulfur ylides, which were generated in situ from α-haloketone oximes and dimethyl sulfonium salts. This approach provides a new method to synthesize a range of 2-isoxazolines in high yields and high regioselectivity. ...
DOI:
10.1016/j.tetlet.2018.12.062

20. Recent applications of magnesium- and Zinc-TMP amides in the synthesis of bioactive targets

Author:
Nishimura, Rodolfo H.V.; Vaz, Artur de L.L.; Bozzini, Leandro A.; Murie, Valter E.; Clososki, Giuliano C.
Source:
Tetrahedron 2019 v.75 no.4 pp. 464-474
ISSN:
0040-4020
Subject:
regioselectivity,   etc   ; amides; chemical reactions; chemical structure; drugs; lithium chloride;     Show all 6 Subjects
Abstract:
... Magnesium- and zinc-TMP amides have come out from relative obscurity to be recognized as important tools in modern synthetic chemistry. Development of LiCl-activated metal amides like TMPMgCl·LiCl and TMP2Zn·2MgCl2·2LiCl has been important to obtain new organometallic reagents through highly chemo- and regioselective reactions. Herein, we review how these reagents are applied in the synthesis of i ...
DOI:
10.1016/j.tet.2018.12.018