scholarly journals Asymmetric Synthesis of Tetrahydroisoquinoline Derivatives through 1,3-Dipolar Cycloaddition of C,N-Cyclic Azomethine Imines with Allyl Alkyl Ketones

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2969
Author(s):  
Guipeng Feng ◽  
Guoyang Ma ◽  
Wenyan Chen ◽  
Shaohong Xu ◽  
Kaikai Wang ◽  
...  
Keyword(s):  
Asymmetric Synthesis ◽  
Functional Groups ◽  
Absolute Configuration ◽  
Dipolar Cycloaddition ◽  
Quantum Electronic ◽  
Mild Conditions ◽  
Spectrum Method ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Azomethine Imines

[3 + 2] A 1,3-Dipolar cycloaddition of C,N-cyclic azomethine imines with allyl alkyl ketones has been achieved. The reaction proceeds under mild conditions and tolerates a wide range of functional groups. An array of tetrahydroisoquinoline derivatives is generally constructed with good diastereoselectivities and enantioselectivities (up to >25:1 dr, >95% ee). Moreover, the absolute configuration of the product was previously determined by using the quantum electronic circular dichroism calculation and ECD spectrum method.

Visible-Light-Triggered Decarboxylative Alkylation of 8-Acylaminoquinoline with N-Hydroxyphthalimide Ester

Synlett ◽  
2020 ◽  
Vol 31 (07) ◽  
pp. 677-682 ◽  
Author(s):  
Bin Sun ◽  
Deyu Li ◽  
Xiaohui Zhuang ◽  
Rui Zhu ◽  
Aertuke Aisha ◽  
...  
Keyword(s):  
Visible Light ◽  
Functional Groups ◽  
Efficient Approach ◽  
Radical Coupling ◽  
Mild Conditions ◽  
Highly Efficient ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Operational Simplicity

A facile protocol for visible-light-induced decarboxylative radical coupling of NHP esters with 8-aminoquinoline amides is reported, affording a highly efficient approach to synthesize a variety of 2-alkylated or 2,4-dialkylated 8-aminoquinoline derivatives. The reaction proceeds smoothly without adding any ligand, and provides the corresponding products containing a wide range of functional groups in moderate to excellent yields. This reaction uses readily available starting materials, and proceeds under mild conditions and with operational simplicity.

Synthesis of 1,3,4-Oxadiazoles by Iodine-mediated Oxidative Cyclization of Methyl Ketones with 4-Phenylsemicarbazide

Synlett ◽  
2021 ◽  
Author(s):  
Shanshan Zhang ◽  
Chuang Liu ◽  
Xiaojun Wu ◽  
Wen Li ◽  
He Li ◽  
...  
Keyword(s):  
Functional Groups ◽  
Oxidative Cyclization ◽  
Methyl Ketones ◽  
One Pot ◽  
Mild Conditions ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Aryl Methyl

An efficient one-pot method to access 5-amino-2-benzoyl-1,3,4-oxadiazoles via I2/DMSO promoted oxidative cyclization of 4-phenylsemicarbazide with (het)aryl methyl ketones under mild conditions was developed. This reaction proceeds smoothly with a wide range of methyl ketones containing different functional groups to give the corresponding products in moderate yields under mild conditions.

Convenient Synthesis of Fluorescent Chromeno[4,3-d]pyrimidines from Electron-Deficient 3-Vinylchromones

Synthesis ◽  
2019 ◽  
Vol 52 (01) ◽  
pp. 40-50 ◽  
Author(s):  
Nikita M. Chernov ◽  
Roman V. Shutov ◽  
Anastasia E. Potapova ◽  
Igor P. Yakovlev
Keyword(s):  
Stokes Shift ◽  
Mild Conditions ◽  
Convenient Synthesis ◽  
Acid Fragment ◽  
Wide Range ◽  
Powerful Approach ◽  
Reaction Proceeds ◽  
Electron Withdrawing Group ◽  
Blue Range ◽  
Acetic Acids

We report an easy and powerful approach to the synthesis of novel chromeno[4,3-d]pyrimidine-5-acetic acids through ANRORC reaction of electron-deficient 3-vinylchromones and 1,3-N,N-binucleophiles. The reaction proceeds under mild conditions (EtOH, rt) and is applicable to a wide range of substrates. The described compounds show fluorescence in the violet-blue range (390–460 nm) with Stokes shift of 40–80 nm and moderate quantum yield (0.15–0.20). As the electron-withdrawing group is conserved in the form of an acetic acid fragment, these compounds may readily be functionalized or conjugated to a required substrate for (bio)analytical purposes.

CuI-Catalyzed [3+2] Cycloaddition of Hindered Vinylidenebisphosphonates (VBP) with Azomethine Imines for Highly Regioselective Access to Dinitrogen-Heterobicycle-Containing Bisphosphonates

Synthesis ◽  
2018 ◽  
Vol 50 (13) ◽  
pp. 2601-2607
Author(s):  
Zhongxiang Zhu ◽  
Qinghe Wang ◽  
Dulin Kong ◽  
Tiao Huang ◽  
Mingshu Wu
Keyword(s):  
Biological Activity ◽  
Low Cost ◽  
Cycloaddition Reaction ◽  
Dipolar Cycloaddition ◽  
Atom Economy ◽  
Mild Conditions ◽  
Synthetic Strategy ◽  
Fused Heterocycles ◽  
Azomethine Imines ◽  
High Stereoselectivity

A concise, atom-economic, and highly regioselective synthetic strategy for the construction of several dinitrogen-fused heterocycles bearing bisphosphonates by 1,3-dipolar cycloaddition reaction of azomethine imines with tetraethyl vinylidene-1,1-bisphosphonate in the presence of CuI in toluene media has been developed. The targeted compounds were obtained in good yields and with excellent regioselectivity. This method for the synthesis of gem-bisphosphonates (BPs) is particularly attractive due to features such as low cost, mild conditions, atom economy, high stereoselectivity, and potential biological activity of the product.

scholarly journals 7-Azaindoline Auxiliary: A Versatile Attachment Facilitating Enantioselective­ C–C Bond-Forming Catalysis

Synthesis ◽  
2018 ◽  
Vol 51 (01) ◽  
pp. 185-193 ◽  
Author(s):  
Naoya Kumagai ◽  
Masakatsu Shibasaki
Keyword(s):  
Asymmetric Catalysis ◽  
Functional Groups ◽  
Conjugate Addition ◽  
Building Blocks ◽  
Short Review ◽  
Dipolar Cycloaddition ◽  
Bond Forming ◽  
Wide Range ◽  
Enantioselective Reactions ◽  
High Stereoselectivity

This short review provides an overview of 7-azaindoline auxiliaries in asymmetric catalysis. 7-Azaindoline serves as a useful attachment to carboxylic acids, and the thus-formed 7-azaindoline amides are amenable to atom-economical C–C bond-forming reactions with high stereoselectivity. The attachment is used for the sake of gaining traction in promoting the reaction of interest and can be easily removed after enantioselective reactions. Both nucleophilic and electrophilic catalyses are realized with broad tolerance for functional groups, showcasing the usefulness of 7-azaindoline auxiliaries for practical and streamlined synthesis of a wide range of acyclic chiral building blocks.1 Introduction2 7-Azaindoline as a Key Auxiliary3 7-Azaindoline Amide as a Pronucleophile3.1 α-Carbon-Substituted 7-Azaindoline Amide3.2 α-Nitrogen-Substituted 7-Azaindoline Amide3.3 α-Oxygen-Substituted 7-Azaindoline Amide3.4 α-Fluorocarbon-Substituted 7-Azaindoline Amide3.5 α-Halogen-Substituted 7-Azaindoline Amide3.6 α-Sulfur-Substituted 7-Azaindoline Amide4 7-Azaindoline Amide as an Electrophile4.1 Conjugate Addition of Butenolides4.2 1,3-Dipolar Cycloaddition of Nitrones5 Transformation of 7-Azaindoline Amide6 Conclusion

Copper-Catalyzed Stereoselective Synthesis of 2-Deoxygalactosides

Synlett ◽  
2020 ◽  
Vol 31 (11) ◽  
pp. 1087-1093 ◽  
Author(s):  
Jianbo Zhang ◽  
Youxian Dong ◽  
Madina Yuma ◽  
Yuling Mei ◽  
Nan Jiang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Stereoselective Synthesis ◽  
Mild Conditions ◽  
Excellent Yield ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Additional Ligand

An efficient glycosylation method to synthesize 2-deoxy-O-galactosides based on a Cu(II)-catalyzed reaction without additional ligand has been developed. The glycosylation was amenable to different protected glycal donors and a wide range of acceptors including alcohols, amino acids, sugars, and phenol, and proceeds with excellent yield and high α-selectivity under mild conditions. The reaction proceeds readily on a gram scale, and its versatility is exemplified in the synthesis of oligosaccharides.

A Selective and Versatile Synthesis of Substituted Chromones via Addition of Phenols to Dimethyl Acetylenedicarboxylate

1995 ◽  
Vol 48 (3) ◽  
pp. 677 ◽  
Author(s):  
MJ Stoermer ◽  
DP Fairlie
Keyword(s):  
Functional Groups ◽  
Addition Reaction ◽  
Initial Step ◽  
High Yield ◽  
Selective Synthesis ◽  
Dimethyl Acetylenedicarboxylate ◽  
Substituted Phenols ◽  
Valuable Component ◽  
Mild Conditions ◽  
Wide Range

Despite many published syntheses of chromones, none has been reported to be both selective for chromones and tolerant of ring substitution. The addition of substituted phenols to dimethyl acetylenedicarboxylate is now reported as a versatile high yield initial step in a simple three-step synthesis of chromone 2-carboxylic acids. Triethylamine being used to deprotonate the substituted phenol, the addition to dimethyl acetylenedicarboxylate proceeds under mild conditions and tolerates a wide range of functional groups on the phenol. Although not stereoselective, both fumarate and maleate aryloxy products of this addition can then be cyclized, according to a known method, to chromones without contamination by isomeric coumarins. Thus the addition reaction is a valuable component of a versatile and selective synthesis of substituted chromones.

Base-Promoted Tandem Cyclization for the Synthesis of Polyfunctional 2-Hydroxy-2,3-dihydrofurans from Arylglyoxal Monohydrates and 3-(1H-Indol-3-yl)-3-oxopropanenitrile

Synlett ◽  
2018 ◽  
Vol 29 (14) ◽  
pp. 1926-1932
Author(s):  
Yi Liu ◽  
An-Xin Wu ◽  
Qun Cai ◽  
Hui-Yang Sheng ◽  
Deng-Kui Li
Keyword(s):  
Functional Groups ◽  
Michael Addition ◽  
Knoevenagel Condensation ◽  
One Pot ◽  
Wide Range ◽  
Reaction Proceeds ◽  
Tandem Cyclization ◽  
Arylglyoxal Monohydrates

An efficient base-promoted tandem cyclization for the synthesis of polyfunctional 2-hydroxy-2,3-dihydrofurans from arylglyoxal monohydrates and 3-(1H-indol-3-yl)-3-oxopropanenitrile has been established. The investigation of the mechanism suggested that this reaction proceeds through a Knoevenagel condensation–Michael addition–oxidation–cyclization sequence. This method demonstrates the compatibility with a wide range of functional groups to produce the 2-hydroxy-2,3-dihydrofuran scaffolds in good to excellent yields in one pot.

A Practical Access to Functionalized Alkyl Sulfinates

Synlett ◽  
2018 ◽  
Vol 29 (12) ◽  
pp. 1622-1626
Author(s):  
M. Haddad ◽  
P. Phansavath ◽  
V. Ratovelomanana-Vidal ◽  
C. Tran ◽  
B. Flamme ◽  
...  
Keyword(s):  
Functional Groups ◽  
Cost Effective ◽  
Good Tolerance ◽  
Mild Conditions ◽  
Cost Effective Method ◽  
Wide Range

We describe herein a three-step synthesis of aliphatic sulfinates. This cost-effective method involves the use of 2-mercaptobenzothiazole under mild conditions and exhibits good yields (up to 78% over three steps). This approach provides an access to a wide range of functionalized sulfinates. A good tolerance with respect to diverse functional groups (alkene, alkyne, ether, acetal) was also noted.

scholarly journals Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

2017 ◽  
Vol 13 ◽  
pp. 2428-2441 ◽  
Author(s):  
Matthias Wünsch ◽  
David Schröder ◽  
Tanja Fröhr ◽  
Lisa Teichmann ◽  
Sebastian Hedwig ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Asymmetric Synthesis ◽  
Functional Groups ◽  
Amide Bond ◽  
Side Chain ◽  
Side Reactions ◽  
Mild Conditions ◽  
Protective Groups ◽  
Polar Functional Groups

The amide moiety of peptides can be replaced for example by a triazole moiety, which is considered to be bioisosteric. Therefore, the carbonyl moiety of an amino acid has to be replaced by an alkyne in order to provide a precursor of such peptidomimetics. As most amino acids have a chiral center at Cα, such amide bond surrogates need a chiral moiety. Here the asymmetric synthesis of a set of 24N-sulfinyl propargylamines is presented. The condensation of various aldehydes with Ellman’s chiral sulfinamide provides chiralN-sulfinylimines, which were reacted with (trimethylsilyl)ethynyllithium to afford diastereomerically pureN-sulfinyl propargylamines. Diverse functional groups present in the propargylic position resemble the side chain present at the Cαof amino acids. Whereas propargylamines with (cyclo)alkyl substituents can be prepared in a direct manner, residues with polar functional groups require suitable protective groups. The presence of particular functional groups in the side chain in some cases leads to remarkable side reactions of the alkyne moiety. Thus, electron-withdrawing substituents in the Cα-position facilitate a base induced rearrangement to α,β-unsaturated imines, while azide-substituted propargylamines form triazoles under surprisingly mild conditions. A panel of propargylamines bearing fluoro or chloro substituents, polar functional groups, or basic and acidic functional groups is accessible for the use as precursors of peptidomimetics.

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