Mechanism of Wittig reaction with cyclic anhydrides

1992 ◽  
Vol 70 (7) ◽  
pp. 1985-1996 ◽  
Author(s):  
Margaret M. Kayser ◽  
Krista L. Hatt ◽  
Donald L. Hooper
Keyword(s):  
Wittig Reaction ◽  
Reaction Pathway ◽  
Spectroscopic Methods ◽  
Cyclic Anhydrides

The reactions of stabilized phosphoranes with cyclic anhydrides give enol-lactones as final products. The initial condensation, however, leads to the formation of acyclic adducts that are observable by NMR, can be easily trapped, and, in some cases, can be isolated. A study of the mechanism of these condensations by NMR spectroscopic methods and by various trapping experiments is described and the reaction pathway is proposed.

A Mechanistic Study of the Wittig Reaction Between a Cyclic Anhydride and a Stabilized Phosphorane

1988 ◽  
Vol 41 (8) ◽  
pp. 1243 ◽  
Author(s):  
AD Abell ◽  
BM Clark ◽  
WT Robinson
Keyword(s):  
Structure Analysis ◽  
Succinic Anhydride ◽  
Wittig Reaction ◽  
Phosphonium Salt ◽  
Mechanistic Study ◽  
Cyclic Anhydride ◽  
X Ray ◽  
Cyclic Anhydrides

The structure of an isolated acyclic intermediate in the Wittig reaction between succinic anhydride and ethoxycarbonylmethylenetriphenylphosphorane has been shown by X-ray structure analysis and DEPT n.m.r .to be the phosphorane (4a) rather than the alternative phosphonium salt (4b). However, an intermediate was not observed in the Wittig reaction between the phosphorane (1b) and cyclic anhydrides. Both the stabilized phosphoranes (1a,b) react with succinic, phthalic and glutaric anhydrides stereoselectively to produce E enol lactones. Some mechanistic aspects are discussed. The assignment of the enol lactone stereochemistry was achieved by n.O.e. difference n.m.r. methods.

Aspects of the mechanism of the Wittig reaction between cyclic anhydrides and stabilized phosphoranes

1982 ◽  
Vol 35 (10) ◽  
pp. 2077 ◽  
Author(s):  
AD Abell ◽  
RA Massy-Westropp
Keyword(s):  
Intermediate Product ◽  
Wittig Reaction ◽  
Product Formation ◽  
Initial Reaction ◽  
Kinetic Control ◽  
Cyclic Anhydrides ◽  
Influence Of Substituents ◽  
Phthalic Anhydrides

It has been established that the Wittig reaction between cyclic anhydrides and methoxycarbonylmethylenetriphenylphosphorane, a reaction used for the preparation of enol-lactones, proceeds via an acyclic intermediate acylated phosphorane for the three classes of anhydrides studied: succinic, maleic and phthalic. The formation of the acyclic intermediate can be irreversible or reversible, depending on the structure of the anhydride. The stereochemistry of the enol-lactones produced is not controlled by the initial reaction of the anhydride with the ylide but either during or after cyclization of the acyclic intermediate. Product formation appears to be under kinetic control with all the anhydrides studied. The influence of substituents in substituted phthalic anhydrides has been investigated.

One-pot synthesis of 4-ethyl 2,3-dimethyl 1-(5-aryl-1,3,4-thiadiazol-2-yl)-5-oxo-2,5-dihydro-1H-pyrrole-2,3,4-tricarboxylate derivatives via intramolecular Wittig reaction

2020 ◽  
Vol 44 (7-8) ◽  
pp. 403-409
Author(s):  
Samin Iravani ◽  
Abbas Ali Esmaeili
Keyword(s):  
Wittig Reaction ◽  
Spectroscopic Methods ◽  
Acetylenic Esters ◽  
One Pot ◽  
Intramolecular Wittig Reaction ◽  
One Pot Synthesis

A facile one-pot synthesis of highly functionalized dialkyl 1-(5-aryl-1,3,4-thiadiazol-2-yl)-4-ethoxy-5-oxo-2,5-dihydro-1 H-pyrrole-2,3-dicarboxylate derivatives via the reaction between acetylenic esters, triphenylphosphine, and ethyl 2-[(5-aryl-1,3,4-thiadiazol-2-yl)amino]-2-oxoacetate is developed. The structure of the products is confirmed by spectroscopic methods.

ChemInform Abstract: A Highly Stereoselective Synthesis of (E)-Enol Lactones by the Wittig Reaction of Cyclic Anhydrides with (α-Alkoxycarbonylethylidene)triphenylphosphorane.

ChemInform ◽  
1987 ◽  
Vol 18 (29) ◽  
Author(s):  
S. TSUBOI ◽  
H. FUKUMOTO ◽  
H. WADA ◽  
A. TAKEDA ◽  
K. FUKUYAMA
Keyword(s):  
Wittig Reaction ◽  
Stereoselective Synthesis ◽  
Cyclic Anhydrides

The Wittig reaction with glutaric and succinic anhydrides

1982 ◽  
Vol 35 (11) ◽  
pp. 2277 ◽  
Author(s):  
AD Abell ◽  
IR Doyle ◽  
RA Massy-Westropp
Keyword(s):  
Wittig Reaction ◽  
Glutaric Anhydride ◽  
Cyclic Anhydrides

Six-membered cyclic anhydrides, including glutaric and some of its alkylated derivatives, have been shown to yield enol-lactones with ethoxycarbonylmethylenetriphenylphosphorane; the (E)isomer is formed preferentially. The reactions of methyl-substituted succinic anhydrides with the same phosphorane give predominantly the (E) enol-lactone in all examples. The influence of alkyl substitutents on the rates of the reactions and the product ratios in both the succinic and glutaric anhydride series is discussed.

On the regioselectivity of Wittig reactions with unsymmetrically substituted succinic anhydrides

1989 ◽  
Vol 67 (9) ◽  
pp. 1401-1410 ◽  
Author(s):  
Margaret M. Kayser ◽  
Livain Breau
Keyword(s):  
Oxygen Atom ◽  
Transition State ◽  
Carbonyl Group ◽  
Wittig Reaction ◽  
Cyclic Anhydrides ◽  
Wittig Reactions ◽  
Deficient Phosphorus

Phosphorane ylids react readily with succinic anhydrides to give enol-lactones. With highly substituted succinic anhydrides, condensations occur at the less substituted carbonyl group, suggesting that the reaction is sterically controlled. This, however, is not the case in monosubstituted anhydrides where effects other than steric become dominant. Condensation of phosphorane 1a with methoxysuccinic anhydride occurs selectively at the carbonyl group adjacent to the substituent. Stabilization of the transition state through complexation between the oxygen atom of the substituent and an electron-deficient phosphorus of the ylid is proposed. Keywords: cyclic anhydrides, Wittig reaction, regioselectivity, stabilized ylid.

On the synthesis and the mechanism of formation of halogenated enol lactones

1997 ◽  
Vol 75 (10) ◽  
pp. 1322-1330 ◽  
Author(s):  
Margaret M. Kayser ◽  
Jun Zhu ◽  
Donald L. Hooper
Keyword(s):  
Reaction Mechanism ◽  
Organic Synthesis ◽  
Wittig Reaction ◽  
Biological Properties ◽  
Mechanism Of Formation ◽  
Direct Route ◽  
Cyclic Anhydrides ◽  
Wittig Reactions

The synthesis of halo enol lactones from cyclic anhydrides via lactonization of the corresponding keto phosphoranes provides a direct route to these interesting compounds, which possess important biological properties and are useful intermediates in organic synthesis. In this paper we outline the syntheses of several halo enol lactones and discuss mechanistic consequences of these reactions on the understanding of Wittig reactions with cyclic anhydrides. Keywords: halolactonization, cyclic anhydrides, halo enol lactones, Wittig reaction mechanism.

ChemInform Abstract: Mechanism of Wittig Reaction with Cyclic Anhydrides.

ChemInform ◽  
2010 ◽  
Vol 24 (11) ◽  
pp. no-no
Author(s):  
M. M. KAYSER ◽  
K. L. HATT ◽  
D. L. HOOPER
Keyword(s):  
Wittig Reaction ◽  
Cyclic Anhydrides

scholarly journals A Highly Stereoselective Synthesis of (E)-Enol Lactones by the Wittig Reaction of Cyclic Anhydrides with (α-Alkoxycarbonylethylidene)triphenylphosphorane

1987 ◽  
Vol 60 (2) ◽  
pp. 689-696 ◽  
Author(s):  
Sadao Tsuboi ◽  
Hirohumi Fukumoto ◽  
Hiroshi Wada ◽  
Akira Takeda ◽  
Keiichi Fukuyama
Keyword(s):  
Wittig Reaction ◽  
Stereoselective Synthesis ◽  
Cyclic Anhydrides

On the mechanism of Wittig reactions with cyclic anhydrides. II.

1993 ◽  
Vol 71 (7) ◽  
pp. 1010-1021 ◽  
Author(s):  
Margaret M. Kayser ◽  
Krista L. Hatt ◽  
Heshui Yu ◽  
Donald L. Hooper
Keyword(s):  
Transition State ◽  
Low Energy ◽  
Spectroscopic Methods ◽  
Selective Transformation ◽  
Π Stacking ◽  
Wittig Olefination ◽  
Reversible Formation ◽  
Cyclic Anhydrides ◽  
Wittig Reactions

A study by NMR spectroscopic methods and trapping experiments of the mechanism of Wittig reactions between stabilized phosphoranes and unsymmetrically substituted cyclic anhydrides suggests that two reactions are involved: (1) a low-energy, reversible formation of acyclic adducts; and (2) a higher energy "Wittig olefination" reaction leading to enol-lactones. The latter, more selective, transformation requires a more highly organized transition state in which π-stacking and stabilizing complexations are important factors.

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