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You searched for: Journal name Organic letters Remove constraint Journal name: Organic letters Publication year rev 7979-2021 Remove constraint Publication year rev: 7979-2021 Source 2021 v.23 no.11 Remove constraint Source: 2021 v.23 no.11
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1. Accessing Aliphatic Amines in C–C Cross-Couplings by Visible Light/Nickel Dual Catalysis

Author:
Weizhe Dong; Shorouk O. Badir; Xuange Zhang; Gary A. Molander
Source:
Organic letters 2021 v.23 no.11 pp. 4250-4255
ISSN:
1523-7052
Subject:
carbonates; catalytic activity; chemoselectivity; light; nickel; peptides; pharmacology; regioselectivity
Abstract:
... A general aminoalkylation of aryl halides was developed, overcoming intolerance of free amines in nickel-mediated C–C coupling. This transformation features broad functional group tolerance and high efficiency. Taking advantage of the fast desilylation of α-silylamines upon single-electron transfer (SET) facilitated by carbonate, α-amino radicals are generated regioselectively, which then engage i ...
DOI:
10.1021/acs.orglett.1c01207

2. Asymmetric Synthesis of Homoallylic Alcohols Featuring Vicinal Tetrasubstituted Carbon Centers via Dual Pd/Photoredox Catalysis

Author:
Sijing Xue; Bart Limburg; Debasish Ghorai; Jordi Benet-Buchholz; Arjan W Kleij
Source:
Organic letters 2021 v.23 no.11 pp. 4447-4451
ISSN:
1523-7052
Subject:
Lewis acids; carbon; catalytic activity; redox reactions; stereoselective synthesis
Abstract:
... Dual palladium/photoredox-catalysis provides an effective method for the decarboxylative asymmetric synthesis of vicinal α,β-tri/tetra- or α,β-tetrasubstituted homoallylic alcohols using Hantzsch-type esters as radical precursors. This mild methodology capitalizes on vinyl cyclic carbonates as accessible reagents providing the target molecules in appreciable to good yields, high branch selectivity ...
DOI:
10.1021/acs.orglett.1c01380

3. Atroposelective Synthesis of Axially Chiral 4-Aryl α-Carbolines via N-Heterocyclic Carbene Catalysis

Author:
Rui Ma; Xiaoxue Wang; Qiaoyu Zhang; Lei Chen; Jian Gao; Jie Feng; Donghui Wei; Ding Du
Source:
Organic letters 2021 v.23 no.11 pp. 4267-4272
ISSN:
1523-7052
Subject:
carbenes; catalytic activity; density functional theory; enantioselectivity; heterocyclic nitrogen compounds
Abstract:
... The first catalytic asymmetric construction of axially chiral 4-aryl α-carboline skeletons has been accomplished through an N-heterocyclic carbene (NHC)-catalyzed atroposelective formal [3 + 3] annulation of 4-nitrophenyl 3-arylpropiolates with 2-sulfonamidoindolines. The synthetic utility of the title compounds has been demonstrated by the diverse late-stage structural modifications. Density func ...
DOI:
10.1021/acs.orglett.1c01221

4. Carbamoyl Anion Addition to Azirines

Author:
Michael J. Kerner; Christian A. Kuttruff; Maxim Chevliakov; Frederic G. Buono; Donghong A. Gao; Mariusz Krawiec; Carl A. Busacca; Chris H. Senanayake; Peter Wipf; Jonathan T. Reeves
Source:
Organic letters 2021 v.23 no.11 pp. 4396-4399
ISSN:
1523-7052
Subject:
diastereoselectivity; dipeptides; ethyleneimine
Abstract:
... The addition of carbamoyl anions to azirines affords synthetically useful 2-aziridinyl amide building blocks. The reaction scope was explored with respect to both formamide and azirine, and the addition was found to be highly diastereoselective. A one-pot conversion of a ketoxime to an aziridinyl amide was demonstrated. The method was employed to incorporate an aziridine residue into a dipeptide s ...
DOI:
10.1021/acs.orglett.1c01334

5. Complementary Site-Selective Sulfonylation of Aromatic Amines by Superacid Activation

Author:
Paul Bourbon; Emeline Appert; Agnès Martin-Mingot; Bastien Michelet; Sébastien Thibaudeau
Source:
Organic letters 2021 v.23 no.11 pp. 4115-4120
ISSN:
1523-7052
Subject:
Lewis acids; aniline; aromatic hydrocarbons; hydrazides; indoles; protonation; regioselectivity; sulfonylation; temperature
Abstract:
... Under superacidic conditions, aniline and indole derivatives are sulfonylated at low temperature with easy-to-access arenesulfonic acids or arenesulfonyl hydrazides. By modification of the functional-group directing effect through protonation, this method allows nonclassical site functionalization by overcoming the innate regioselectivity of electrophilic aromatic substitution. This superacid-medi ...
DOI:
10.1021/acs.orglett.1c00994

6. Convergent Synthesis of Tetrasaccharide Fragment of Cervimycin K

Author:
Jihun Kang; Young Ho Rhee
Source:
Organic letters 2021 v.23 no.11 pp. 4468-4472
ISSN:
1523-7052
Subject:
glycosides; moieties; oligosaccharides
Abstract:
... A new synthetic approach toward oligosaccharides consisting only of 2,3,6-trideoxypyranoglycosides is reported. The key feature is highlighted by the convergent approach that allows the introduction of the aglycon moiety in the late stage of the synthesis. As an illustrative example, the tetrasaccharide portion of cervimycin K was prepared as cyclohexyl glycoside. ...
DOI:
10.1021/acs.orglett.1c01404

7. Copper-Catalyzed Three-Component Carboboronation of Allenes Using Highly Strained Cyclic Ketimines as Electrophiles

Author:
Hao Deng; Yujie Dong; Yu Shangguan; Fazhou Yang; Sheng Han; Jiaqi Wu; Bo Liang; Hongchao Guo; Cheng Zhang
Source:
Organic letters 2021 v.23 no.11 pp. 4431-4435
ISSN:
1523-7052
Subject:
Lewis acids; boron compounds; chlorination; copper; diastereoselectivity; ketimines
Abstract:
... A diastereoselective copper and NHC-ligand-catalyzed three-component difunctionalization of allenes with bis(pinacolato)diboron and 2H-azirines to afford borylated allylaziridines is described. The reaction exhibits complete diastereoselectivity and good yields, and the further chlorination of the corresponding borylated products was also performed. It is believed that the high ring-strain force o ...
DOI:
10.1021/acs.orglett.1c01372

8. Copper-Catalyzed Vicinal Cyano-, Thiocyano-, and Chlorophosphorylation of Alkynes: A Phosphinoyl Radical-Initiated Approach for Difunctionalized Alkenes

Author:
Ze-Kun Tao; Cheng-Kun Li; Jian-An Li; Adedamola Shoberu; Wei Zhang; Jian-Ping Zou
Source:
Organic letters 2021 v.23 no.11 pp. 4342-4347
ISSN:
1523-7052
Subject:
alkenes; alkynes; phosphine; phosphonates; stereoselectivity
Abstract:
... A copper-catalyzed difunctional cyano-, thiocyano-, and chlorophosphorylation reaction of alkynes with P(O)–H compounds and coupling partners (TBACN, TMSNCS, TMSCl) is described. The reaction introduces versatile groups (−P(O)R₂ and −CN, −SCN, or −Cl) to form tri- and tetrasubstituted alkenyl phosphine oxides/phosphonates regio- and stereoselectively. ...
DOI:
10.1021/acs.orglett.1c01286

9. Cu-Catalyzed Dehydrogenative C–O Cyclization for the Synthesis of Furan-Fused Thienoacenes

Author:
Koichi Mitsudo; Yoshiaki Kobashi; Kaito Nakata; Yuji Kurimoto; Eisuke Sato; Hiroki Mandai; Seiji Suga
Source:
Organic letters 2021 v.23 no.11 pp. 4322-4326
ISSN:
1523-7052
Subject:
dehydrogenation; ethylene glycol; furans; solvents; toluene
Abstract:
... The first Cu-catalyzed dehydrogenative C–O cyclization for the synthesis of furan-fused thienoacenes is described. A variety of heteroacenes including a thieno[3,2-b]furan or a thieno[2,3-b]furan skeleton were synthesized by intramolecular C–H/O–H coupling. The use of a mixed solvent of N-methyl-2-pyrrolidone, ethylene glycol monomethyl ether, and toluene was essential for suppressing side reactio ...
DOI:
10.1021/acs.orglett.1c01256

10. Dehydrative Allylation of Alkenyl sp² C–H Bonds

Author:
Xinying Cai; Huicong Xing; Ju Qiu; Bowen Li; Peizhong Xie
Source:
Organic letters 2021 v.23 no.11 pp. 4368-4373
ISSN:
1523-7052
Subject:
alkenes; allylation; cleavage (chemistry); cross-coupling reactions; regioselectivity
Abstract:
... We designed a cooperative catalytic system by combining commercially available Ca(NTf₂)PF₆ and Pd(PPh₃)₄ to address the dehydrative allylation of alkenyl sp² C–H bonds in an environmentally benign manner. A novel C–OH bond cleavage method was found to be crucial for this practical protocol. A variety of alkenes and allylic alcohols equipped with wide-spectrum functional groups can be successfully ...
DOI:
10.1021/acs.orglett.1c01309

11. Diastereoselective Synthesis of Tetracyclic Tetrahydroquinoline Derivative Enabled by Multicomponent Reaction of Isocyanide, Allenoate, and 2-Aminochalcone

Author:
Zhishuang Wang; Youwen Fei; Chongrong Tang; Lei Cui; Jie Shen; Kun Yin; Shanya Lu; Jian Li
Source:
Organic letters 2021 v.23 no.11 pp. 4094-4098
ISSN:
1523-7052
Subject:
diastereoselective synthesis; diastereoselectivity; feedstocks
Abstract:
... We report here a multicomponent protocol to assemble several polycyclic dihydropyran-fused tetrahydroquinoline structures with excellent diastereoselectivity. This procedure employs simple feedstocks to accomplish a series of diverse structures, which is difficult to attain by traditional sequences. ...
DOI:
10.1021/acs.orglett.1c00912

12. Divergent Synthesis of Aziridine and Imidazolidine Frameworks under Blue LED Irradiation

Author:
Xiao Cheng; Bao-Gui Cai; Hui Mao; Juan Lu; Lei Li; Kun Wang; Jun Xuan
Source:
Organic letters 2021 v.23 no.11 pp. 4109-4114
ISSN:
1523-7052
Subject:
cycloaddition reactions; density functional theory; ethyleneimine; irradiation; light; reaction mechanisms; redox reactions
Abstract:
... We develop a visible light-promoted divergent cycloaddition of α-diazo esters with hexahydro-1,3,5-triazines, leading to a series of aziridine and imidazolidine frameworks in average good yield, by simply changing the reaction media used. It is noteworthy that the reaction occurs under sole visible light irradiation without the need for exogenous photoredox catalysts. More significantly, a reasona ...
DOI:
10.1021/acs.orglett.1c00979

13. Enantioselective Addition of Azlactones to Ethylene Sulfonyl Fluoride via Dual Catalysis

Author:
Dong-yu Zhu; Xue-jing Zhang; Ming Yan
Source:
Organic letters 2021 v.23 no.11 pp. 4228-4232
ISSN:
1523-7052
Subject:
amino acids; catalytic activity; drugs; enantioselectivity; ethylene; hydrogen bonding
Abstract:
... Enantioselective conjugate addition of azlactones to ethylene sulfonyl fluoride has been achieved via the cooperative catalysis with (DHQD)₂PHAL and a hydrogen-bond donor (HBD). This approach furnishes a facile access to a range of structurally diverse azlactone sulfonyl fluoride derivatives with good to excellent yields and enantioselectivities. The combination of azlactone and sulfonyl fluoride ...
DOI:
10.1021/acs.orglett.1c01193

14. Fe-Catalyzed Intramolecular B–H/C–H Dehydrogenative Coupling: Synthesis of Carborane-Fused Nitrogen Heterocycles

Author:
Yu Chen; Hairong Lyu; Yangjian Quan; Zuowei Xie
Source:
Organic letters 2021 v.23 no.11 pp. 4163-4167
ISSN:
1523-7052
Subject:
aminoquinolines; carbon-hydrogen bond activation; dehydrogenation; regioselectivity
Abstract:
... We disclose herein the first example of iron-catalyzed regioselective intramolecular C–H/B–H dehydrogenative coupling, affording unprecedented C,B-substituted carborane-fused phenanthroline derivatives. The 8-aminoquinoline type auxiliaries not only serve as the bidentate directing groups but also ingeniously become the core part of the final products. The mechanistic hypothesis includes B–H activ ...
DOI:
10.1021/acs.orglett.1c01104

15. Gold(I)-Catalyzed Cyclization–3-Aza-Cope–Mannich Cascade and Its Application to the Synthesis of Cephalotaxine

Author:
Takeo Sakai; Chise Okumura; Masatoshi Futamura; Naotaka Noda; Akari Nagae; Chiharu Kitamoto; Madoka Kamiya; Yuji Mori
Source:
Organic letters 2021 v.23 no.11 pp. 4391-4395
ISSN:
1523-7052
Subject:
cyclization reactions; heterocyclic nitrogen compounds; tertiary amines
Abstract:
... The discovery of a new gold(I)-catalyzed cascade reaction involving cyclization onto a vinylammonium, 3-aza-Cope rearrangement, and Mannich cyclization is reported. A variety of fused nitrogen heterocycles were prepared from simple cyclic tertiary amines using 1–5 mol % of a AuCl(PPh₃)/Ag[C₅(CN)₅] cocatalyst system. The developed reaction was used in a study aimed at synthesizing cephalotaxine. A ...
DOI:
10.1021/acs.orglett.1c01323

16. Harnessing In Situ Radical Oxygenation: Copper-Catalyzed Interrupted Azirine–Alkyne Ring-Expansion Reaction for the Synthesis of Pyrrolones

Author:
Chandragiri Sujatha; Madhu Nallagangula; Kayambu Namitharan
Source:
Organic letters 2021 v.23 no.11 pp. 4219-4223
ISSN:
1523-7052
Subject:
catalytic activity; copper; oxygen
Abstract:
... Here we report a novel interrupted azirine–alkyne ring-expansion reaction with molecular oxygen for the direct synthesis of highly functionalized pyrrolones enabled by copper catalysis. Mechanistic investigations indicate that the present three-component reaction proceeds via two copper-catalyzed sequential reactions, an azirine-ring-opening alkynylation and an amine-directed radical oxygenation, ...
DOI:
10.1021/acs.orglett.1c01162

17. Highly Stereoselective Intramolecular Carbofluorination of Internal α,β-Ynones Promoted by Selectfluor

Author:
Bingbin Zhu; Hang Han; Wei-Ke Su; Boan Yan; Zhi Li; Chuanming Yu; Xinpeng Jiang
Source:
Organic letters 2021 v.23 no.11 pp. 4488-4492
ISSN:
1523-7052
Subject:
aldehydes; chelation; fluorine; oxygen; sodium; stereoselectivity
Abstract:
... Herein, we report a metal-free intramolecular carbofluorination protocol for the synthesis of tetrasubstituted monofluoroalkenes from internal α,β-ynones and Selectfluor with both high stereoselectivity and broad functional group tolerance. The chelation between tetrafluoroborate anion and the oxygen present in the aldehyde group rendered the reaction highly stereoselective, with the tetrafluorobo ...
DOI:
10.1021/acs.orglett.1c01441

18. Iridium-Catalyzed Isomerization/Cycloisomerization/Aromatization of N-Allyl-N-sulfonyl-o-(λ¹-silylethynyl)aniline Derivatives to Give Substituted Indole Derivatives

Author:
Jiawei Qiu; Makoto Sako; Tomoyuki Tanaka; Tsuyoshi Matsuzaki; Tsunayoshi Takehara; Takeyuki Suzuki; Shohei Ohno; Kenichi Murai; Mitsuhiro Arisawa
Source:
Organic letters 2021 v.23 no.11 pp. 4284-4288
ISSN:
1523-7052
Subject:
aniline; aromatization; indoles; isomerization
Abstract:
... We have developed a one-iridium-catalyst system that transforms N-allyl-N-sulfonyl-2-(silylalkynyl)aniline derivatives, which are 1,7-enynes in which both multiple bonds have a heteroatom, to the corresponding substituted indole derivatives via isomerization/cycloisomerization/aromatization. This strategy provides an atom-economical and straightforward synthetic approach to a series of valuable in ...
DOI:
10.1021/acs.orglett.1c01231

19. JBIR-155, a Specific Class D β-Lactamase Inhibitor of Microbial Origin

Author:
Takehiro Nishimura; Teppei Kawahara; Noritaka Kagaya; Yusuke Ogura; Hirosato Takikawa; Hikaru Suenaga; Masaatsu Adachi; Takatsugu Hirokawa; Takayuki Doi; Kazuo Shin-ya
Source:
Organic letters 2021 v.23 no.11 pp. 4415-4419
ISSN:
1523-7052
Subject:
Streptomyces; moieties; spectral analysis
Abstract:
... We discovered JBIR-155 as a novel specific class D β-lactamase inhibitor from Streptomyces polymachus SoB100815Hv02. JBIR-155 consists of a 6-oxabicyclo[3.2.0]heptan-7-one skeleton and a long unsaturated alkyl chain moiety of which absolute configuration was determined by spectroscopic data, modified Mosher’s method, and analyses of the relative configuration of chemically modified derivative. JBI ...
DOI:
10.1021/acs.orglett.1c01352

20. Kinetic Resolution of 2,2-Disubstituted Dihydroquinolines through Chiral Phosphoric Acid-Catalyzed C6-Selective Asymmetric Halogenations

Author:
Chaofan Zhu; Wei Liu; Fei Zhao; Yunrong Chen; Houchao Tao; Yu-Peng He; Xiaoyu Yang
Source:
Organic letters 2021 v.23 no.11 pp. 4104-4108
ISSN:
1523-7052
Subject:
catalytic activity; phosphoric acid; regioselectivity
Abstract:
... A novel kinetic resolution of 2,2-disubstituted dihydroquinolines was achieved by regioselective asymmetric halogenations enabled by chiral phosphoric acid catalysis. A series of dihydroquinolines bearing 2,2-disubstitutions were well-tolerated in these reactions, generating both the recovered dihydroquinolines and C-6-brominated products with high enantioselectivities, with s-factors up to 149. I ...
DOI:
10.1021/acs.orglett.1c00978