An ionic chain mechanism for the substitution of an acetate group by the 2-Nitropropan-2-ide ion in benzylidene diacetates

1976 ◽  
Vol 29 (2) ◽  
pp. 327 ◽  
Author(s):  
DJ Freeman ◽  
PJ Newcombe ◽  
RK Norris
Keyword(s):  
Good Yield ◽  
Dimethyl Sulphoxide ◽  
Acetate Group ◽  
Chain Mechanism ◽  
Elimination Reaction ◽  
Nucleophilic Cleavage ◽  
Enol Acetates ◽  
Subsequent Elimination

The reaction of 16 arylmethylene diacetates [benzylidene diacetates; ArCH(OAc)2] with lithium 2-nitropropan-2-ide in dimethyl sulphoxide has been studied. With the exception of aryl rings bearing strongly electron-donating substituents a ready reaction takes place giving l-aryl-2-methyl-2-nitropropyl acetates in good yield. The mechanism of this reaction, in which an acetate group is formally substituted by a (CH3)2C(N02) group, has been shown to be an ionic chain mechanisminvolving nucleophilic cleavage of the diacetate to catalytic quantities of the corresponding arene carbaldehyde (ArCHO) which subsequently undergoes a Henry condensation followed by a transacetylation reaction. In some cases (nitro heteroaromatic derivatives) a subsequent elimination reaction gives enol-acetates [ArC(OAc)=C(CH3)2].

Phosphonium salts. III. The action of cyanide ion and other nucleophiles on some bis-phosphonium salts

1969 ◽  
Vol 22 (7) ◽  
pp. 1405 ◽  
Author(s):  
JJ Brophy ◽  
MJ Gallagher
Keyword(s):  
Sodium Azide ◽  
Sodium Methoxide ◽  
Sodium Acetate ◽  
Potassium Cyanide ◽  
Dimethyl Sulphoxide ◽  
High Yield ◽  
Phosphonium Salts ◽  
Elimination Reaction ◽  
Cyanide Ion ◽  
Reaction Proceeds

Cyclic and acyclic bis-phosphonium salts with a two-carbon bridge are smoothly cleaved to phosphines in high yield by potassium cyanide in dimethyl sulphoxide. Evidence is presented that the reaction proceeds by an elimination-addition sequence. An elimination reaction also occurs when sodium methoxide, sodium azide, sodium acetate, and triethylamine react with ethane-1,2-bis(tri-phenylphosphonium) dibromide. ��� In a novel reaction, triphenylphosphine is converted into its oxide by a mixture of sodium azide and dimethyl sulphoxide.

scholarly journals A Selective Catalytic Method of Enol-acetylation under Microwave Irradiation

1999 ◽  
Vol 23 (6) ◽  
pp. 404-405
Author(s):  
Dipok J. Kalita ◽  
Ruli Borah ◽  
Jadab C. Sarma
Keyword(s):  
Acetic Anhydride ◽  
Microwave Irradiation ◽  
Good Yield ◽  
Catalytic Amount ◽  
Cyclic Ketones ◽  
Catalytic Method ◽  
Enol Acetates

Six-membered cyclic ketones on treatment with acetic anhydride and a catalytic amount of iodine under microwave irradiation give the corresponding enol acetates in good yield.

Highly regioselective synthesis of 4-tosylthiomorpholine via intramolecular cyclization of N-tethered thioalkenols

2016 ◽  
Vol 14 (44) ◽  
pp. 10489-10495 ◽  
Author(s):  
Anil K. Saikia ◽  
Manash J. Deka ◽  
Upasana Borthakur
Keyword(s):  
Intramolecular Cyclization ◽  
Regioselective Synthesis ◽  
Elimination Reaction ◽  
One Pot ◽  
Metal Free ◽  
Subsequent Elimination

A one-pot, metal-free procedure has been developed for the synthesis of 4-tosylthiomorpholine from N-tethered thioalkenols via bromination, cyclization and subsequent elimination reaction in good yields. The reaction is highly regioselective.

Radical C(sp3)–H alkenylation, alkynylation and allylation of ethers and amides enabled by photocatalysis

2017 ◽  
Vol 19 (11) ◽  
pp. 2530-2534 ◽  
Author(s):  
Subhasis Paul ◽  
Joyram Guin
Keyword(s):  
Good Yield ◽  
Radical Addition ◽  
Elimination Reaction

A photocatalytic radical addition/elimination reaction that enables direct C(sp3)–H alkenylation, alkynylation and allylation of ethers/amides with good yield and stereoselectivity.

Nickel-Catalyzed Inter- and Intramolecular Carbon-Sulfur Bond Metathesis by Reversible Arylation

2019 ◽  
Author(s):  
Tristan Delcaillau ◽  
Alessandro Bismuto ◽  
Zhong Lian ◽  
Bill Morandi
Keyword(s):  
Good Yield ◽  
Functional Group ◽  
Product Formation ◽  
Single Bond ◽  
Ring Closing Metathesis ◽  
Catalytic Systems ◽  
Metathesis Reactions ◽  
New Applications ◽  
Further Development ◽  
Sulfur Bond

A nickel-catalyzed carbon-sulfur bond metathesis has been developed to access high-value thioethers. 1,2-bis(dicyclohexylphosphino)ethane (dcype) is essential to promote this highly functional group tolerant reaction. Further, synthetically challenging macrocycles could be obtained in good yield in an unusual example of ring-closing metathesis which does not involve alkene bonds. In-depth organometallic studies support a reversible Ni(0)-Ni(II) pathway to product formation. Overall, this work does not only disclose a more sustainable and more functional group tolerant alternative to previous catalytic systems based on Pd, but also presents new applications and mechanistic information which are highly relevant to the further development and application of unusual single bond metathesis reactions.

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