Small organic molecules with tailored structures: initiators in the transition-metal-free C–H arylation of unactivated arenes

Small organic molecules hold great promise for phototheranostics due to their well-defined chemical structures and optical properties, excellent biodegradation and biocompatibility, high purity, and outstanding repeatability. Nevertheless, many small molecules...

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Transition-Metal-Free, Intermolecular Azidoheteroarylation of Alkenes: Efficient Access to β-Azidoalkylated Quinoxalinones and Preliminary Antifungal Evaluation Against Magnaporthe grisea

Synthesis ◽

10.1055/s-0040-1707514 ◽

2020 ◽

Vol 52 (16) ◽

pp. 2395-2409

Author(s):

Weiwei Qin ◽

Zhaodong Li ◽

Yiming Du ◽

Yue Chen ◽

Yun-Lin Liu

Keyword(s):

Transition Metal ◽

Magnaporthe Grisea ◽

Single Step ◽

Domino Reaction ◽

Efficient Synthesis ◽

Metal Free ◽

Efficient Access ◽

First Time ◽

Antibacterial Evaluation ◽

Addition Pathway

An efficient, PhI(OAc)2-mediated, radical azidoheteroarylation of alkenes under transition-metal-free conditions is reported by employing TMSN3 and quinoxalin-2(1H)-ones as coupling partners. This domino reaction allows an eﬃcient synthesis of valuable orangoazides containing quinoxalin-2(1H)-one derivatives and could be extended to phosphinyl-alkylated quinoxalin-2(1H)-one in a single step in moderate to excellent yields under mild conditions, as demonstrated by the preliminary antibacterial evaluation against Magnaporthe grisea for the first time. Mechanistic studies revealed that this transformation undergoes a cascade addition pathway controlled by a polar radical.

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Aldehydes as powerful initiators for photochemical transformations

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.76 ◽

2020 ◽

Vol 16 ◽

pp. 833-857 ◽

Cited By ~ 7

Author(s):

Maria A Theodoropoulou ◽

Nikolaos F Nikitas ◽

Christoforos G Kokotos

Keyword(s):

Transition Metal ◽

Organic Synthesis ◽

Organic Molecules ◽

Photophysical Properties ◽

Organic Transformations ◽

Aliphatic Aldehydes ◽

Small Organic Molecules ◽

Photochemical Transformations ◽

The Way

Photochemistry, the use of light to promote organic transformations, has been known for more than a century but only recently has revolutionized the way modern chemists are thinking. Except from transition metal-based complexes, small organic molecules have been introduced as catalysts or initiators. In this review, we summarize the potential that (aromatic or aliphatic) aldehydes have as photoinitiators. The photophysical properties and photoreactivity of benzaldehyde are initially provided, followed by applications of aldehydes as initiators for polymerization reactions. Finally, the applications to date regarding aldehydes as photoinitiators in organic synthesis are presented.

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Synthesis of Imidazo[1,5-a]quinolines via Metal-Free Oxidative Amination of sp3 C–H Bonds

Synthesis ◽

10.1055/s-0037-1610137 ◽

2018 ◽

Vol 50 (14) ◽

pp. 2761-2767 ◽

Cited By ~ 7

Author(s):

Chen Ma ◽

Huanhuan Liu ◽

Xinfeng Wang

Keyword(s):

Amino Acids ◽

Transition Metal ◽

Intramolecular Cyclization ◽

Efficient Synthesis ◽

Oxidative Amination ◽

Metal Free ◽

Oxidation System

A novel oxidative amination of sp3 C–H bonds was developed for the efficient synthesis of imidazo[1,5-a]quinolines from readily available α-amino acids and (2-azaaryl)methanes. This domino protocol, which was established in a TBAI-TBHP oxidation system, includes transition-metal-free decarboxylation and intramolecular cyclization. This method represented a new avenue for the synthesis of N-heterocycles using 2-methylquinolines as the synthon of quinoline-2-carbaldehydes.

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Transition-metal-free C–C bond cleavage and formation: efficient synthesis of 2,3-diarylimidazo[1,2-α]pyridines from 2-aminopyridines and alkynoates

RSC Advances ◽

10.1039/c6ra19291b ◽

2016 ◽

Vol 6 (89) ◽

pp. 86464-86467 ◽

Cited By ~ 5

Author(s):

Zhengwang Chen ◽

Yuelu Wen ◽

Guotian Luo ◽

Min Ye ◽

Qinghao Wang

Keyword(s):

Transition Metal ◽

Bond Cleavage ◽

Cyclization Reaction ◽

Efficient Synthesis ◽

Metal Free ◽

Highly Efficient

A highly efficient transition-metal-free cyclization reaction for the synthesis of 2,3-diarylimidazo[1,2-α]pyridines is described.

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Transition metal–assisted carbonization of small organic molecules toward functional carbon materials

Science Advances ◽

10.1126/sciadv.aat0788 ◽

2018 ◽

Vol 4 (7) ◽

pp. eaat0788 ◽

Cited By ~ 56

Author(s):

Zhen-Yu Wu ◽

Shi-Long Xu ◽

Qiang-Qiang Yan ◽

Zhi-Qin Chen ◽

Yan-Wei Ding ◽

...

Keyword(s):

Transition Metal ◽

Organic Molecules ◽

Carbon Materials ◽

Small Organic Molecules

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Synthesis of di(hetero)aryl sulfides by defluorinative sulfenylation of polyfluoroalkyl ketones with sodium sulfinates or arylsulfonyl chlorides

Chemical Communications ◽

10.1039/d0cc03303k ◽

2020 ◽

Vol 56 (61) ◽

pp. 8699-8702

Author(s):

Xue-Qiang Chu ◽

Ting Xie ◽

Ya-Wen Wang ◽

Xiang-Rui Li ◽

Weidong Rao ◽

...

Keyword(s):

Transition Metal ◽

Cascade Reactions ◽

Efficient Synthesis ◽

Metal Free ◽

Aryl Sulfides ◽

Aryl Sulfide

Cascade reactions of α-perfluoroalkyl ketones with sodium sulfinates or arylsulfonyl chlorides that allowed the efficient synthesis of fluoroalkylated di(hetero)aryl sulfide derivatives under transition metal-free conditions were developed.

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Importance of Chiral Recognition in Designing Metal-Free Ligands for G-Quadruplex DNA

Molecules ◽

10.3390/molecules24081473 ◽

2019 ◽

Vol 24 (8) ◽

pp. 1473 ◽

Cited By ~ 2

Author(s):

Dora M. Răsădean ◽

Samuel W. O. Harrison ◽

Isobel R. Owens ◽

Aucéanne Miramont ◽

Frances M. Bromley ◽

...

Keyword(s):

Amino Acid ◽

Chiral Recognition ◽

Organic Molecules ◽

Small Organic Molecules ◽

Quadruplex Dna ◽

Metal Free ◽

G Quadruplex ◽

Dna Stabilization

Four pairs of amino acid-functionalized naphthalenediimide enantiomers (d- and l-lysine derived NDIs) were screened toward G-quadruplex forming sequences in telomeres (h-TELO) and oncogene promoters: c-KIT1, c-KIT2, k-RAS and BCL-2. This is the first study to address the effect of point chirality toward G-quadruplex DNA stabilization using purely small organic molecules. Enantioselective behavior toward the majority of ligands was observed, particularly in the case of parallel conformations of c-KIT2 and k-RAS. Additionally, Nε-Boc-l-Lys-NDI and Nε-Boc-d-Lys-NDI discriminate between quadruplexes with parallel and hybrid topologies, which has not previously been observed with enantiomeric ligands.

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Application of α-amino acids for the transition-metal-free synthesis of pyrrolo[1,2-a]quinoxalines

Organic & Biomolecular Chemistry ◽

10.1039/c7ob01688c ◽

2017 ◽

Vol 15 (34) ◽

pp. 7157-7164 ◽

Cited By ~ 9

Author(s):

Huanhuan Liu ◽

Feiyu Zhou ◽

Wen Luo ◽

Yuxin Chen ◽

Chenyang Zhang ◽

...

Keyword(s):

Amino Acids ◽

Transition Metal ◽

Functional Group ◽

Efficient Synthesis ◽

Metal Free

A practical and concise protocol for the efficient synthesis of pyrrolo[1,2-a]quinoxalines from readily available α-amino acids and 2-(1H-pyrrol-1-yl)anilines under transition metal-free conditions has been established. This protocol, which includes the formation of new C–C and C–N bonds, features a wide substrate scope with a broad range of functional group tolerance.

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