ChemInform Abstract: Revisiting Wittig Olefination and Aza-Wittig Reaction for Carbohydrate Transformations and Stereocontrol in Sugar Chemistry.

ChemInform ◽  
2014 ◽  
Vol 45 (50) ◽  
pp. no-no
Author(s):  
Vasco Cachatra ◽  
Amelia P. Rauter
Keyword(s):  
Wittig Reaction ◽  
Sugar Chemistry ◽  
Wittig Olefination

scholarly journals A Wittig-olefination–Claisen-rearrangement approach to the 3-methylquinoline-4-carbaldehyde synthesis

2012 ◽  
Vol 8 ◽  
pp. 1725-1729 ◽  
Author(s):  
Mukund G Kulkarni ◽  
Mayur P Desai ◽  
Deekshaputra R Birhade ◽  
Yunus B Shaikh ◽  
Ajit N Dhatrak ◽  
...  
Keyword(s):  
Efficient Method ◽  
Wittig Reaction ◽  
Claisen Rearrangement ◽  
Aldehyde Group ◽  
Oxidative Cleavage ◽  
Reductive Cyclization ◽  
Vinyl Ethers ◽  
Terminal Olefin ◽  
Wittig Olefination ◽  
Step Procedure

Efficient syntheses are described for the synthetically important 3-methylquinoline-4-carbaldehydes 6a–h from o-nitrobenzaldehydes 1a–h employing a Wittig-olefination–Claisen-rearrangement protocol. The Wittig reaction of o-nitrobenzaldehydes with crotyloxymethylene triphenylphosphorane afforded crotyl vinyl ethers 2a–h, which on heating under reflux in xylene underwent Claisen rearrangement to give 4-pentenals 3a–h. Protection of the aldehyde group of the 4-pentenals as acetals 4a–h and subsequent oxidative cleavage of the terminal olefin furnished nitroaldehydes 5a–h. Reductive cyclization of these nitroaldehydes yielded the required 3-methylquinoline-4-carbaldehydes 6a–h in excellent yields. Therefore, an efficient method was developed for the preparation of 3-methylquinoline-4-carbaldehydes from o-nitrobenzaldehydes in a simple five-step procedure.

scholarly journals Solvent reduced wittig olefination reactions with halo containing conjugated phosphoranes

2006 ◽  
Vol 4 (3) ◽  
Author(s):  
Thies Thiemann ◽  
Yasuko Tanaka ◽  
Keiko Ideta ◽  
Shuntaro Mataka
Keyword(s):  
Wittig Reaction ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Analogous Reaction ◽  
Cross Coupling Reaction ◽  
Wittig Olefination ◽  
Olefination Reactions

AbstractThe Wittig reaction of carbaldehydes with alkoxycarbonylhalomethylidenetriphenylphosphoranes can be performed with ease in solventless systems. The analogous reaction of carbaldehydes with acylhalomethylidenetriphenylphosphoranes requires a small amount of solvent, such as chloroform, in order for the reaction to proceed. The products of the reaction are versatile precursors for further transformations, such as the Suzuki-Miyaura cross-coupling reaction.

scholarly journals Characterization and Synthesis of Some α, β-unsaturated Ester Derivatives from Aliphatic Aldehydes

2010 ◽  
Vol 2 (2) ◽  
pp. 343-350
Author(s):  
M. A. Bari ◽  
M.M. Karim ◽  
M. M. Hoque ◽  
M. A. J. Miah
Keyword(s):  
Large Scale ◽  
Wittig Reaction ◽  
Acid Ethyl Ester ◽  
Aliphatic Aldehyde ◽  
Diazo Compounds ◽  
Unsaturated Ester ◽  
Reaction Conditions ◽  
Wittig Olefination ◽  
Synthetic Intermediates

Ethyl diazoacetate compound is useful synthetic intermediates for α, β-unsaturated ester in organic synthesis but, due to its toxicity and unpredictable explosive behaviour, its unique reactivity has not been fully exploited and the use on large scale has been avoided. We have developed a reliable method that generates EDA compound in situ. Our approach is based on the Wittig reaction, which utilizes EDA as diazo precursors. In the presence of Cu(OTf)2, we found that diazo compounds can be cleanly converted to alkenyl compounds under mild reaction conditions and in a narrow range of solvents. These diazo compounds can then be induced to react directly with aldehydes to synthesize olefin. We have shown the usefulness of this chemistry in a number of different transformations, such as Wittig olefination reactions chemistry as applied toward the synthesis of more complicated molecules. Keywords:  α, β-unsaturated ester; Acryclic acid ethyl ester; Aliphatic aldehyde; Cu(II) triflate; Triphenylphosphine. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i2.4167               J. Sci. Res. 2 (2), 343-350 (2010) 

Boron-Wittig olefination with gem-bis(boryl)alkanes

2021 ◽  
Author(s):  
Ana B. Cuenca ◽  
Elena Fernández
Keyword(s):  
Wittig Reaction ◽  
Carbonyl Derivatives ◽  
Wittig Olefination

Boron-Wittig reaction as the condensation of lithium α-bis(boryl)carbanions with carbonyl derivatives on route to substituted borylalkenes.

Facile Synthesis of (E)-5-Styrylpyrimidines via Wittig Reaction Using So-dium Tripolyphosphate in Water

2020 ◽  
Vol 17 ◽  
Author(s):  
Anilkumar S. Patel ◽  
Sahaj A. Gandhi ◽  
Rajesh D. Modh ◽  
Urmila H. Patel ◽  
Yogesh T. Naliapara ◽  
...  
Keyword(s):  
Wittig Reaction ◽  
Sodium Tripolyphosphate ◽  
Facile Synthesis ◽  
Aryl Aldehydes ◽  
Wittig Olefination ◽  
High Yields ◽  
Very High

Abstract: An inexpensive and eco-friendly Wittig olefination protocol has been developed to prepare novel (E)-5-styrylpy-rimidines. The reaction of pyrimidine phosphonium ylide with different aryl/hetero-aryl aldehydes underwent smoothly in the presence of sodium tripolyphosphate (STPP) in aqueous condition giving (E)-5-styrylpyrimidines (10a-t) in very high yields (77-96 %).

Double Ring-Closing Approach for the Synthesis of 2,3,6,7-Substituted Anthracene Derivatives

2020 ◽  
Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer
Keyword(s):  
Wittig Reaction ◽  
Condensation Reaction ◽  
Synthetic Methods ◽  
Anthracene Derivative ◽  
Double Ring ◽  
Mild Conditions ◽  
Wide Range ◽  
Anthracene Derivatives

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>

Computational Study on the Kinetics and Mechanisms of Unimolecular Reactions of (Z)-(Z)-N-(λ5-phosphanylidene) Formohydrazonic Formic Anhydride: Intramolecular aza-Wittig Reaction in Competition with Mumm Rearrangement

2020 ◽  
Vol 17 (11) ◽  
pp. 884-889
Author(s):  
Somayeh Mirdoraghi ◽  
Hamed Douroudgari ◽  
Farideh Piri ◽  
Morteza Vahedpour
Keyword(s):  
Rate Constants ◽  
Density Functional ◽  
Wittig Reaction ◽  
Computational Study ◽  
Single Step ◽  
Low Energy ◽  
Coupled Cluster ◽  
Unimolecular Reaction ◽  
Single Step Reaction ◽  
Good Agreement

For (Z)-(Z)-N-(λ5-phosphanylidene) formohydrazonic formic anhydride, Aza-Wittig reaction and Mumm rearrangement are studied using both density functional and coupled cluster theories. For this purpose, two different products starting from one substrate are considered that are competing with each other. The obtained products, P1 and P2, are thermodynamically favorable. The product of the aza-Wittig reaction, P1, is more stable than the product of Mumm rearrangement (P2). For the mentioned products, just one reliable pathway is separately proposed based on unimolecular reaction. Therefore, the rate constants based on RRKM theory in 300-600 K temperature range are calculated. Results show that the P1 generation pathway is a suitable path due to low energy barriers than the path P2. The first path has three steps with three transition states, TS1, TS2, and TS3. The P2 production path is a single-step reaction. In CCSD level, the computed barrier energies are 14.55, 2.196, and 10.67 kcal/mol for Aza-Wittig reaction and 42.41 kcal/mol for Mumm rearrangement in comparison with the corresponding complexes or reactants. For final products, the results of the computational study are in a good agreement with experimental predictions.

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