Catalyst-Free Synthesis of Chromane-Type N,O-Acetals via Intramolecular Addition of Phenols to Enamines

Synthesis ◽  
2020 ◽  
Vol 52 (23) ◽  
pp. 3604-3621 ◽  
Author(s):  
Vitaly A. Osyanin ◽  
Dmitry V. Osipov ◽  
Irina V. Melnikova ◽  
Kirill S. Korzhenko ◽  
Irina A. Semenova ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Secondary Amines ◽  
Catalyst Free ◽  
Reaction Proceeds ◽  
New Strategy

A new strategy to 2-aminochromanes through catalyst-free cascade reaction of 3-trifluoroacetyl-4H-chromenes and 4H-chromene-3-carbaldehydes with cyclic secondary amines is presented. The reaction proceeds through subsequent 1,4- and 1,2-additions of amine, bimolecular elimination of trifluoroacetamide or formamide, and 6-exo-trig cyclization. The latter stage is a very rare example of addition of phenols to enamines. The obtained semicyclic N,O-acetals were applied as useful precursors for the synthesis of other chromanes.

A metal-free radical cascade reaction of phosphine oxides with 2-aryloxy phenylacetylenes to assemble diphosphonyl xanthene derivatives

2021 ◽  
Author(s):  
Tao Fan ◽  
Yan Liu ◽  
Caina Jiang ◽  
Yanli Xu ◽  
Yan-Yan Chen
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Cascade Reaction ◽  
Phosphine Oxides ◽  
Metal Free ◽  
Mild Conditions ◽  
Xanthene Derivatives ◽  
Reaction Proceeds ◽  
Radical Cascade

A radical cascade reaction of 2-aryloxy phenylacetylene with phosphine oxides promoted by K2S2O8 was developed, provided diphosphonyl xanthenes as products. This reaction proceeds under transition metal-free and mild conditions with...

Alkene Difunctionalization Directed by Free Amines: Diamine Synthesis via Nickel-Catalyzed 1,2-Carboamination

2021 ◽  
Author(s):  
Taeho Kang ◽  
José Manuel González ◽  
Zi-Qi Li ◽  
Klement Foo ◽  
Peter Cheng ◽  
...  
Keyword(s):  
Nickel Catalyst ◽  
Room Temperature ◽  
Kinetic Studies ◽  
Fine Tuning ◽  
Secondary Amines ◽  
Protecting Group ◽  
Wide Range ◽  
Leaving Group ◽  
Primary And Secondary Amines ◽  
Reaction Proceeds

A versatile method to access differentially substituted 1,3- and 1,4-diamines via a nickel-catalyzed three-component 1,2-carboamination of alkenyl amines with aryl/alkenylboronic ester nucleophiles and N–O electrophiles is reported. The reaction proceeds efficiently with free primary and secondary amines without needing a directing auxiliary or protecting group, and is enabled by fine-tuning the leaving group on the N–O reagent. The transformation is highly regioselective and compatible with a wide range of coupling partners and alkenyl amine substrates, all performed at room temperature. A series of kinetic studies support a mechanism in which alkene coordination to the nickel catalyst is turnover-limiting.

Diversity-Oriented Synthesis via Catalyst-Free Addition of Ketones to [e]-Fused 1H-Pyrrole-2,3-diones

Synthesis ◽  
2018 ◽  
Vol 50 (24) ◽  
pp. 4897-4904 ◽  
Author(s):  
Ekaterina Stepanova ◽  
Andrey Maslivets ◽  
Svetlana Kasatkina ◽  
Maksim Dmitriev
Keyword(s):  
Intramolecular Cyclization ◽  
Aromatic Hydrocarbons ◽  
Michael Addition ◽  
Aldol Reaction ◽  
Synthetic Approach ◽  
Reaction Conditions ◽  
Diversity Oriented Synthesis ◽  
Catalyst Free ◽  
Solvent Free Conditions ◽  
Reaction Proceeds

A facile synthetic approach towards two distinct pyrrole-based heterocyclic scaffolds has been developed by the interaction of 1H-pyrrole-2,3-diones fused at the [e]-side to a 1,4-benzoxazin-2-one or quinoxalin-2(1H)-one moiety with ketones. The described interaction proceeds either as an aldol reaction or as a Michael addition/intramolecular cyclization depending on the reaction conditions. The disclosed aldol reaction proceeds with good diastereoselectivity under catalyst-free conditions when the reaction is carried out in aromatic hydrocarbons. Products of the cascade Michael addition/intramolecular cyclization reaction are predominantly formed under catalyst-free and solvent-free conditions. The proposed strategy provides facile access to pharmaceutically interesting pyrrole-based polyheterocycles.

Catalyst-free facile synthesis of polycyclic indole/pyrrole substituted-1,2,3-triazoles

2019 ◽  
Vol 17 (35) ◽  
pp. 8153-8165 ◽  
Author(s):  
Jitendra Gour ◽  
Srikanth Gatadi ◽  
Ravikumar Akunuri ◽  
Madhavi Venkata Yaddanapudi ◽  
Mushtaq Ahmad Nengroo ◽  
...  
Keyword(s):  
Cascade Reaction ◽  
Free Access ◽  
Facile Synthesis ◽  
Reaction Conditions ◽  
Catalyst Free

A general and catalyst-free access to the fused polycyclic N-heterocycles via an intramolecular azide–alkene cascade reaction under mild reaction conditions has been developed.

Electrochemical fabrication of fibrin gels via cascade reaction for cell culture

2019 ◽  
Vol 55 (37) ◽  
pp. 5335-5338 ◽  
Author(s):  
Noriko Taira ◽  
Kosuke Ino ◽  
Tatsuki Kumagai ◽  
Yuji Nashimoto ◽  
Hitoshi Shiku
Keyword(s):  
Cell Culture ◽  
Cascade Reaction ◽  
Fibrin Gels ◽  
New Strategy ◽  
Electrochemical Fabrication

We present a new strategy for fabricating fibrin gels by electrochemically controlling a cascade reaction and its application in cell culture.

tert-Butyl nitrite promoted transamidation of secondary amides under metal and catalyst free conditions

2019 ◽  
Vol 17 (4) ◽  
pp. 845-850 ◽  
Author(s):  
Popuri Sureshbabu ◽  
Sadaf Azeez ◽  
Priyanka Chaudhary ◽  
Jeyakumar Kandasamy
Keyword(s):  
Tert Butyl ◽  
Catalyst Free ◽  
Reaction Proceeds ◽  
Secondary Amides

Transamidation of secondary amides with various amines is demonstrated using tert-butyl nitrite. The reaction proceeds through the N-nitrosamide intermediate and provides the desired products in excellent yields.

Copper(II)-Promoted Oxidation/[3+2]Cycloaddition/Aromatization Cascade: Efficient Synthesis of Tetrasubstituted NH-Pyrrole from Chalcones and Iminodiacetates

Synlett ◽  
2019 ◽  
Vol 30 (12) ◽  
pp. 1442-1446 ◽  
Author(s):  
Zhang-qi Lin ◽  
Chao-dong Li ◽  
Zi-chun Zhou ◽  
Shuai Xue ◽  
Jian-rong Gao ◽  
...  
Keyword(s):  
Efficient Method ◽  
Cascade Reaction ◽  
Oxidative Cyclization ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
Highly Efficient ◽  
Wide Range ◽  
Reaction Proceeds

A simple and highly efficient method for the preparation of tetrasubstituted NH-pyrrole from a wide range of chalcones and diethyl iminodiacetates via a Cu(OAc)2-promoted oxidation/[3+2]cycloaddition/aromatization cascade reaction has been developed. This reaction proceeds through dehydrogenations, deamination, and oxidative cyclization, affording the corresponding products in good to excellent yields. This convenient methodology for constructing tetrasubstituted NH-pyrroles has several advantages over existing methods, such as the use of easily accessible chalcones and readily available diethyl iminodiacetates, and mild reaction conditions. A wide range of substrates are tolerated.

Catalyst free C–N bond formation by the reaction of amines with diimides: bulky guanidines

2015 ◽  
Vol 39 (9) ◽  
pp. 7503-7510 ◽  
Author(s):  
Ashim Baishya ◽  
Thota Peddarao ◽  
Milan Kr. Barman ◽  
Sharanappa Nembenna
Keyword(s):  
Bond Formation ◽  
Secondary Amines ◽  
Catalyst Free ◽  
Direct Addition

Catalyst free direct addition of cyclic secondary amines to various N,N′-bisaryl substituted carbodiimides led to the formation of bulky guanidines. Furthermore, two equivalents of N,N′-bisaryl substituted carbodiimides upon treatment with piperazine led to the formation of bis guanidines.

Nucleophilic attack on the carbon–carbon double bond. I. Reaction of primary and secondary amines with 2,2-di(4-nitrophenyl)-1,1-difluoroethene

1986 ◽  
Vol 64 (12) ◽  
pp. 2274-2278 ◽  
Author(s):  
Kenneth T. Leffek ◽  
Urszula Maciejewska
Keyword(s):  
Order Reaction ◽  
Secondary Amines ◽  
Nucleophilic Attack ◽  
Ammonium Ions ◽  
Third Order ◽  
First Order ◽  
Enthalpy Of Activation ◽  
Catalysed Reaction ◽  
Primary And Secondary Amines ◽  
Reaction Proceeds

The reaction of primary and secondary amines with 2,2-di(4-nitrophenyl)-1,1-difluoroethene (1) in acetonitrile solvent gives first 2,2-di(4-nitrophenyl)-1-fluoro-1-aminoethene (2) and then 2,2-di(4-nitrophenyl)-1,1-difluoro-1-aminoethane (3). With excess amine, pseudo-first-order rate constants for the production of 2 were measured, which showed a second-order reaction, together with a catalysed third-order reaction. In addition to the reagent amines, the reaction is also catalysed by tertiary amines and bases such as oxalate and acetate, but not by chloride and perchlorate, nor by ammonium ions. The enthalpy of activation for the reaction of piperidine with 1 in acetonitrile is 3.7 kcalmol−1, but for the catalysed reaction an apparent value of −2.2 kcal mol−1 was obtained. It is concluded that the reaction proceeds via a pre-equilibrium to a zwitterion, followed by another equilibrium giving a carbanion that yields the product (2) by a rate-determining cleavage of the carbon–fluorine bond.

Catalyst-Free One-Pot Reductive Alkylation of Primary and Secondary Amines and N,N-Dimethylation of Amino Acids Using Sodium Borohydride in 2,2,2-Trifluoroethanol

Synthesis ◽  
2010 ◽  
Vol 2011 (03) ◽  
pp. 490-496 ◽  
Author(s):  
Mahmood Tajbakhsh ◽  
Rahman Hosseinzadeh ◽  
Heshmatollah Alinezhad ◽  
Somayeh Ghahari ◽  
Akbar Heydari ◽  
...  
Keyword(s):  
Amino Acids ◽  
Sodium Borohydride ◽  
Secondary Amines ◽  
Reductive Alkylation ◽  
One Pot ◽  
Catalyst Free ◽  
Primary And Secondary Amines
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