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

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.

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

Synthesis ◽

10.1055/s-0040-1707209 ◽

2020 ◽

Vol 52 (23) ◽

pp. 3604-3621 ◽

Cited By ~ 1

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.

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The reaction between 2,2-di(4-nitrophenyl)1,1,1-trifluoroethane and tert-butoxide ion in tert-butyl alcohol solvent

Canadian Journal of Chemistry ◽

10.1139/v80-314 ◽

1980 ◽

Vol 58 (18) ◽

pp. 1979-1982 ◽

Cited By ~ 1

Author(s):

Arnold Jarczewski ◽

Kenneth T. Leffek

Keyword(s):

Isotope Effects ◽

Activation Parameters ◽

Butyl Alcohol ◽

Blue Colour ◽

Butyl Ether ◽

Tert Butyl ◽

Kinetic Isotope ◽

Tert Butyl Alcohol ◽

Reaction Proceeds ◽

Alcohol Solvent

The reaction between 2,2-di(4-nitrophenyl) 1,1,1-trifluoroethane and excess sodium tert-butoxide in tert-butyl alcohol takes place rapidly to yield first the olefin, by elimination of HF. This is followed by a slower addition of tert-butoxide to the olefin, which upon reaction with the solvent gives the tert-butyl ether as the final product. The blue anions involved in each of these reactions are observed.Rate constants, the primary deuterium kinetic isotope effects, and the activation parameters have been measured for the appearance of the initial blue colour and also for the formation of the olefin. It is concluded that the reaction proceeds by a reversible ElcB mechanism.

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Solvent- and catalyst-free aza-Michael addition of imidazoles and related heterocycles

10.26434/chemrxiv.11877039 ◽

2020 ◽

Author(s):

Katharina Kodolitsch ◽

Florian Gobec ◽

Christian Slugovc

Keyword(s):

Michael Addition ◽

Catalyst Free ◽

Michael Acceptor ◽

Reaction Proceeds ◽

Azole Derivative ◽

Small Excess

This work demonstrates the scope and limitations of the aza-Michael addition of imidazoles and related heterocycles with electron deficient olefins under solvent- and catalyst-free conditions. The reaction proceeds at 80°C within hours towards completion as long as the azole derivative is sufficiently soluble in the Michael acceptor, which has been used in small excess. Workup only comprises evaporation of surplus Michael-acceptor and no additional solvents are necessary for purifying the products.<br>

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A Practical Synthesis of 3‐Functionalized Coumarins from o ‐Cresols and Active Methylene Compounds under Metal and Catalyst‐Free Conditions Using tert ‐Butyl Hydrogen Peroxide

ChemistrySelect ◽

10.1002/slct.202002263 ◽

2020 ◽

Vol 5 (29) ◽

pp. 9030-9033

Author(s):

Swati Chauhan ◽

Pratibha Verma ◽

Jeyakumar Kandasamy ◽

Vandana Srivastava

Keyword(s):

Hydrogen Peroxide ◽

Tert Butyl ◽

Catalyst Free ◽

Active Methylene Compounds ◽

Practical Synthesis ◽

Active Methylene

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Deoxygenative hydroboration of primary and secondary amides: A catalyst- free and solvent-free approach

Chemical Communications ◽

10.1039/d1cc04148g ◽

2021 ◽

Author(s):

Rohit Kumar ◽

Milan Kumar Bisai ◽

Shailja Jain ◽

Kumar Vanka ◽

Sakya Singha Sen

Keyword(s):

Solvent Free ◽

Catalyst Free ◽

Secondary Amides

In contrast to the recent reports on catalytic hydroboration of amides to amines with pinacolborane (HBpin), a simple catalyst-free and solvent-free method for the hydroboration of a variety of amides...

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Oxidative Asymmetric Formal Aza-Diels–Alder Reactions of Tetrahydro-β-carboline with Enones in the Synthesis of Indoloquinolizidine-2-ones

Molecules ◽

10.3390/molecules23092228 ◽

2018 ◽

Vol 23 (9) ◽

pp. 2228 ◽

Cited By ~ 2

Author(s):

Xiang Wu ◽

Shi-Bao Zhao ◽

Lang-Lang Zheng ◽

You-Gui Li

Keyword(s):

Oxidative Dehydrogenation ◽

Alder Reaction ◽

Diels Alder ◽

Diastereoselective Synthesis ◽

Butyl Hydroperoxide ◽

Unsaturated Ketones ◽

Tert Butyl ◽

Diels Alder Reaction ◽

Tert Butyl Hydroperoxide ◽

Reaction Proceeds

Ru-catalyzed tandem amine oxidative dehydrogenation/formal aza-Diels–Alder reaction for enantio- and diastereoselective synthesis of indoloquinolizidine-2-ones from tetrahydro-β-carbolines and α,β-unsaturated ketones is described. The reaction proceeds via tandem ruthenium-catalyzed amine dehydrogenation using tert-butyl hydroperoxide (TBHP) as the oxidant and a chiral thiourea-catalyzed formal aza-[4 + 2] cycloaddition, providing a step-economical strategy for the synthesis of these valuable heterocyclic products.

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Solvent- and catalyst-free aza-Michael addition of imidazoles and related heterocycles

10.26434/chemrxiv.11877039.v1 ◽

2020 ◽

Author(s):

Katharina Kodolitsch ◽

Florian Gobec ◽

Christian Slugovc

Keyword(s):

Michael Addition ◽

Catalyst Free ◽

Michael Acceptor ◽

Reaction Proceeds ◽

Azole Derivative ◽

Small Excess

This work demonstrates the scope and limitations of the aza-Michael addition of imidazoles and related heterocycles with electron deficient olefins under solvent- and catalyst-free conditions. The reaction proceeds at 80°C within hours towards completion as long as the azole derivative is sufficiently soluble in the Michael acceptor, which has been used in small excess. Workup only comprises evaporation of surplus Michael-acceptor and no additional solvents are necessary for purifying the products.<br>

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Transition Metal Catalyst Free Cross-Coupling Reaction of Tertiary Propargylic Alcohols with Hetero-Areneboronic Acids

10.26434/chemrxiv-2021-rbm7n ◽

2021 ◽

Author(s):

Jian-Fei Bai ◽

Jianbo Tang ◽

Xiaolong Gao ◽

Zhi-Jiang Jiang ◽

Zhanghua Gao

Keyword(s):

Transition Metal ◽

Coupling Reaction ◽

Cross Coupling ◽

Metal Catalyst ◽

Transition Metal Catalyst ◽

Propargylic Alcohols ◽

Catalyst Free ◽

Cross Coupling Reaction ◽

Reaction Proceeds ◽

Acid Catalyzed

We report a perfluorophenylboronic acid catalyzed cross coupling reaction of tertiary propargylic alcohols and hetero-areneboronic acids for valuable benzo[b]thiophene and cyclopenta[a]indene derivates. This coupling reaction proceeds efficiently with a wide array of substrates scope in up to 89% yield and excellent regioselectivity. A significant advantage of our protocol is the transition metal catalyst free and mild conditions needed. This strategy provides direct and facile access to medicinally important benzo[b]thiophene and cyclopenta[a]indene scaffold containing a quaternary carbon center.

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