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You searched for: Journal Tetrahedron letters Remove constraint Journal: Tetrahedron letters Publication Year 2021 Remove constraint Publication Year: 2021 Source 2021 v.66 Remove constraint Source: 2021 v.66
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1. AIBN initiated functionalization of the benzylic sp3 C[sbnd]H and C[sbnd]C bonds in the presence of dioxygen

Author:
Hu, Yingying; Shao, Yu; Zhang, Shuwei; Yuan, Yuan; Sun, Zheng; Yuan, Yu; Jia, Xiaodong
Source:
Tetrahedron letters 2021 v.66 pp. 152806
ISSN:
0040-4039
Subject:
benzophenones; carbon-hydrogen bond activation; catalysts; cleavage (chemistry); exhibitions; oxygen
Abstract:
... A sp³ CH bond functionalization and CC bond cleavage were realized by AIBN/O₂ catalyst system, providing a series of benzophenones under mild reaction conditions. The mechanistic study shows that a peroxide intermediate is involved in this transformation, and in the case of diphenylmethanes, the sp³ CC bond is cleaved through the peroxide rearrangement, which might provides a new way to cleave rel ...
DOI:
10.1016/j.tetlet.2020.152806

2. A practical and efficient method for late-stage deuteration of terminal alkynes with silver salt as catalyst

Author:
Wu, Ding-Chuan; Bai, Jing-Wen; Guo, Lei; Hu, Guang-Qi; Liu, Kai-Hui; Sheng, Fei-Fei; Zhang, Hong-Hai; Sun, Zheng-Yi; Shen, Kang; Liu, Xiang
Source:
Tetrahedron letters 2021 v.66 pp. 152807
ISSN:
0040-4039
Subject:
alkynes; ambient temperature; catalysts; deuterium; moieties; protocols; silver
Abstract:
... A practical and efficient H/D exchange method for selective deuteration of terminal alkynes was disclosed. The reaction was simply performed with CF₃COOAg as catalyst at room temperature, affording products with high level of deuterium incorporation. The excellent site-selectivity and promising functional group tolerance of this protocol enabled deuteration of pharmaceuticals and nature product de ...
DOI:
10.1016/j.tetlet.2020.152807

3. A simple and efficient synthesis of benzofuroquinolines via the decarboxylative cross-coupling

Author:
Rathod, Praveen Kumar; Jonnalagadda, Sowmya; Panaganti, Leelavathi
Source:
Tetrahedron letters 2021 v.66 pp. 152808
ISSN:
0040-4039
Subject:
Lewis bases; acids; cross-coupling reactions; oxidation; quinolines; synthesis; yields
Abstract:
... An efficient and simple synthesis of benzofuroquinoline derivatives, a biologically important condensed heterocyclic system is presented. A range of benzofuro[2.3-b]quinolines were accessed by applying palladium-catalysed decarboxylative cyclisation from 2-(2- haloaryloxy)quinoline-3-carboxylic acids, which in turn are effortlessly obtained from 2-chloro-3-formylquinolines by nucleophilic substitu ...
DOI:
10.1016/j.tetlet.2020.152808

4. Brønsted acid-catalyzed Friedel-Crafts-type alkylation of arenes with α-aryl diazoacetates

Author:
Chen, Wenming; Chen, Guifang; Wang, Biao; Wang, Wei; Huang, Wei; Tian, Xu
Source:
Tetrahedron letters 2021 v.66 pp. 152751
ISSN:
0040-4039
Subject:
acetates; alkylation; aromatic hydrocarbons; protocols; yields
Abstract:
... An efficient Brønsted acid-catalyzed Friedel-Crafts-type alkylation of arenes with α-aryl diazoacetates has been developed. This protocol enables effective access to various highly functionalized diarylmethane derivatives in moderate to high yields. Moreover, the product of selected diaryl acetate could be transformed to β, β-diaryl substituted γ-butyrolactone. ...
DOI:
10.1016/j.tetlet.2020.152751

5. Cobalt-catalyzed synthesis of bromomonofluoroallyl ketones by addition of alkynes and α-bromo-α-fluoroketones

Author:
Ren, Jie; Fu, Xiaoyi; Hou, Yali; Wu, Jingjing; Wu, Fanhong
Source:
Tetrahedron letters 2021 v.66 pp. 152805
ISSN:
0040-4039
Subject:
alkynes; ambient temperature; ketones; synthesis
Abstract:
... The first example of Co-catalyzed monofluoroalkylation of alkynes with α-bromo-α-fluoroketones was established for the synthesis of a variety of bromomonofluoroallyl ketones. The reactions were successfully accomplished at room temperature, which were mild and efficient. The mechanism investigation showed that a radical pathway was involved. ...
DOI:
10.1016/j.tetlet.2020.152805

6. Construction of supramolecular hyperbranched polymers based on a tetrathiafulvalene derivative: Self-assembly and charge transfer interaction with TCNQ

Author:
Li, Xing-Long; Qin, Jie; Jiang, Man; Chen, Meng-Ning; Wang, Rong-Zhou; Yu, Shengsheng; Wang, Hai-Ying; Xing, Ling-Bao
Source:
Tetrahedron letters 2021 v.66 pp. 152823
ISSN:
0040-4039
Subject:
Cucurbitaceae; crosslinking; diameter; hydrogen; light scattering; nanoparticles; nuclear magnetic resonance spectroscopy; polymers; transmission electron microscopy; ultraviolet-visible spectroscopy; water; zeta potential
Abstract:
... In the present work, a four naphthyl-armed tetrathiafulvalene derivative (TTFB) was designed and synthesized through one-step reaction. Based on the host–guest interaction between naphthyl and cucurbit[8]uril (CB[8]), supramolecular hyperbranched polymers (SHPs) can be constructed in water, depending on hydrogen nuclear magnetic resonance (¹H NMR) spectra, UV–vis absorption spectroscopy and diffus ...
DOI:
10.1016/j.tetlet.2021.152823

7. Efforts towards a Noyori reduction of a 3-fluorpiperidin-4-one with dynamic kinetic resolution

Author:
LePaih, Jacques; Goff, Dane A.; Singh, Rajinder; Shaw, Simon J.
Source:
Tetrahedron letters 2021 v.66 pp. 152764
ISSN:
0040-4039
Subject:
crystallization; enantiomers; enantioselectivity
Abstract:
... A Noyori reduction of racemic 1-Boc-3-fluoropiperidin-4-one has been achieved under dynamic kinetic resolution conditions that results in a single cis enantiomer being obtained with both diastereo- and enantioselectivity > 90%. This medicinal chemistry building block can be generated on multi-gram scale using the developed conditions to a single enantiomer in a 60% yield after employing a crystall ...
DOI:
10.1016/j.tetlet.2020.152764

8. Highly chemoselective and enantioselective recognition of serine by a fluorescent probe

Author:
Wang, Yalin; Tian, Jun; Zhao, Feng; Chen, Yu; Huo, Bingyi; Yu, Shanshan; Yu, Xiaoqi; Pu, Lin
Source:
Tetrahedron letters 2021 v.66 pp. 152803
ISSN:
0040-4039
Subject:
chemoselectivity; enantioselectivity; fluorescence; fluorescent dyes; serine
Abstract:
... A diarylacetylene-containing 1,1′-bi-2-naphthol derivative (R)-2 was designed and synthesized. This compound in combination with Zn²⁺ represents the first chemoselective as well as enantioselective fluorescent probe for the biologically important amino acid serine. It was found that l-serine can greatly enhance the fluorescence of the probe at λ = 471 nm but d-serine and 17 other common amino acid ...
DOI:
10.1016/j.tetlet.2020.152803

9. Luminescence properties of cyclometalated platinum(II) complexes in a dichloromethane/n-hexane system

Author:
Tao, Weitong; Chen, Yan; Lu, Lu; Liu, Chun
Source:
Tetrahedron letters 2021 v.66 pp. 152802
ISSN:
0040-4039
Subject:
deterioration; exhibitions; hydrogen bonding; nanosheets; phosphorescence; platinum; vibration
Abstract:
... The luminescence properties of three neutral cyclometalated Pt(II) complexes were investigated in a CH₂Cl₂/n-hexane system. The diphenylamino and trifluoromethyl modified Pt2 exhibits aggregation-induced phosphorescent emission (AIPE) feature. The crystal stacking of Pt2 shows that the intermolecular hydrogen bonding restricts both intramolecular rotation (RIR) and vibration (RIV), which weakens t ...
DOI:
10.1016/j.tetlet.2020.152802

10. Organotin-catalyzed synthesis of hydroxyalkylamides from lactones via a ring-opening process

Author:
Liang, Xiayu; Yu, Peng; Fu, Chen; Shen, Yongcun
Source:
Tetrahedron letters 2021 v.66 pp. 152821
ISSN:
0040-4039
Subject:
acetates; dibutyltin; lactones; synthesis
Abstract:
... A new strategy for the facile synthesis of hydroxyalkylamides through the ring-opening reaction of lactone with amine promoted by dibutyltin acetate was developed. A series of hydroxyalkylamide compounds were obtained and the method was successfully applied to the synthesis of pharmaceutically active molecules tyrosinase inhibitor V and HDAC inhibitor VI via a three-step synthetic pathway. The bro ...
DOI:
10.1016/j.tetlet.2021.152821

11. Palladium-catalyzed prenylation of (hetero)aryl boronic acids

Author:
Leister, Jeffrey; Chao, Darrian; Billingsley, Kelvin L.
Source:
Tetrahedron letters 2021 v.66 pp. 152800
ISSN:
0040-4039
Subject:
boronic acids; catalysts; catalytic activity; cross-coupling reactions; ligands; palladium; regioselectivity
Abstract:
... Prenyl or dimethylallyl groups are common structural motifs in natural products and small molecule therapeutics. In this report, we describe a palladium-catalyzed method for the cross-coupling of aryl and heteroaryl boronic acids with prenyl alcohol. Catalyst systems based on dialkylbiaryl phosphines were highly active for this transformation. These supporting ligands provided opportunities for tu ...
DOI:
10.1016/j.tetlet.2020.152800

12. Short asymmetric syntheses of sphinganine [(2S,3R)-2-aminooctadecane-1,3-diol] and its C(2)-epimer

Author:
Da Silva Pinto, Solange; Davies, Stephen G.; Fletcher, Ai M.; Newton, Sophie K.; Roberts, Paul M.; Thomson, James E.
Source:
Tetrahedron letters 2021 v.66 pp. 152743
ISSN:
0040-4039
Subject:
diastereoselectivity; lithium; oxidation; protocols; sphinganine; stereoselective synthesis; stereospecificity
Abstract:
... A short asymmetric synthesis of sphinganine [(2S,3R)-2-aminooctadecane-1,3-diol] and its C(2)-epimer is reported. The synthesis of sphinganine employs diastereoselective aminohydroxylation of tert-butyl 2-octadecenoate [conjugate addition of lithium (S)-N-benzyl-N-(α-methylbenzyl)amide, then in situ enolate oxidation with (+)-camphorsulfonyloxaziridine (CSO)] and a stereospecific rearrangement of ...
DOI:
10.1016/j.tetlet.2020.152743

13. Synthesis of novel 4-substituted 1,2,3-thiadiazoles via iodine-catalyzed cyclization reactions

Author:
Li, Weiwei; Li, Xuezhen; Feng, Yijiao; Liu, Ping; Ma, Xiaowei; Zhao, Jixing
Source:
Tetrahedron letters 2021 v.66 pp. 152824
ISSN:
0040-4039
Subject:
cyclization reactions; sulfur; synthesis
Abstract:
... Iodine-catalyzed the reaction of substituted methyl ketone N-tosylhydrazones with elemental sulfur has been developed. The cyclizations of the ester-substituted N-tosylhydrazone substrates proceeded smoothly under optimal reaction conditions, and the corresponding products 4-alkyl-1, 2, 3-thiadiazoles are obtained. For the reaction of 4-arylbutan-2-one of N-tosylhydrazone substrates, (E)-4-styryl- ...
DOI:
10.1016/j.tetlet.2021.152824

14. Synthesis of 25X-BOMes and 25X-NBOHs (X = H, I, Br) for pharmacological studies and as reference standards for forensic purposes

Author:
Alves de Barros, Wellington; Queiroz, Marcelo Pereira; da Silva Neto, Leonardo; Borges, Graziele Martins; Martins, Felipe Terra; de Fátima, Ângelo
Source:
Tetrahedron letters 2021 v.66 pp. 152804
ISSN:
0040-4039
Subject:
X-radiation; forensic sciences; hydroxybenzaldehyde; reference standards; synthesis
Abstract:
... An expeditious method is reported for the synthesis of three NBOHs (25H-, 25I- and 25B-NBOH; 9–38% overall yield) and three NBOMes (25H-, 25I- and 25B-NBOMe; 7–33% overall yield) from salicylaldehyde and 2-methoxyaldehyde, respectively. The X-ray structures of 25H-, 25I- and 25B-NBOH.HCl were also determined. Our approach should provide a general entry for preparing such a class of substances for ...
DOI:
10.1016/j.tetlet.2020.152804

15. Total synthesis of indiacen A using a practical one-pot reaction: Promoted by a key waste product, and its utility in natural products synthesis

Author:
Wang, Lihua; Lei, Ting; Wang, Fusheng; Jiang, Shizhi; Yan, Guiyang
Source:
Tetrahedron letters 2021 v.66 pp. 152822
ISSN:
0040-4039
Subject:
catalysts; synthesis; wastes
Abstract:
... Trialkylammonium salt, recognized as a waste product in the Heck reaction, was found to act as a key catalyst in the practical one-pot Heck-dehydration reaction. A concise synthesis of indiacen A was accomplished in 92% overall yield using a protecting-group-free and redox-neutral strategy. In this synthesis, a novel one-pot reaction with high regio- and stereo-selectivity was developed and furthe ...
DOI:
10.1016/j.tetlet.2021.152822

16. Towards the total synthesis of aurodox: Preparation of the key hemiacetal-lactone

Author:
Ohara, Motoyoshi; Ikeda, Akari; Nakajima, Asuka; Ōno, Takanori; Noguchi, Yoshihiko; Watanabe, Akito; Hirose, Tomoyasu; Sunazuka, Toshiaki
Source:
Tetrahedron letters 2021 v.66 pp. 152799
ISSN:
0040-4039
Subject:
alkenes; degradation; epoxidation reactions; synthesis
Abstract:
... We describe the preparation of a cyclic hemiacetal-lactone 6, which is a key intermediate in the total synthesis of Aurodox (1) and also a degradation product of aurodox. The bicyclic core of 6 was obtained by lactonization and hemiacetalization after stereo-selective epoxidation at late stage. The construction of olefins utilized a Wittig reaction and a Horner-Wadsworth-Emmons reaction using d-pa ...
DOI:
10.1016/j.tetlet.2020.152799