Hydrophobic Encapsulated Phosphonium Salts-Synthesis of Weakly Coordinating Cations and their Application in Wittig Reactions

2015 ◽  
Vol 21 (25) ◽  
pp. 9119-9125 ◽  
Author(s):  
Ralf Moritz ◽  
Manfred Wagner ◽  
Dieter Schollmeyer ◽  
Martin Baumgarten ◽  
Klaus Müllen
Keyword(s):  
Phosphonium Salts ◽  
Weakly Coordinating ◽  
Wittig Reactions

SYNTHESIS OF ISOTOPICALLY LABELLED OLEFINS VIA THE WITTIG REACTION

1965 ◽  
Vol 43 (5) ◽  
pp. 1614-1624 ◽  
Author(s):  
J. G. Atkinson ◽  
M. H. Fisher ◽  
D. Horley ◽  
A. T. Morse ◽  
R. S. Stuart ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dimethyl Sulfoxide ◽  
Wittig Reaction ◽  
Low Molecular Weight ◽  
Phosphonium Salts ◽  
Reaction Conditions ◽  
Selective Labelling ◽  
Wittig Reactions

A new application of the Wittig reaction to the preparation of olefins of low molecular weight which allows selective labelling in the vinyl or allyl positions with isotopes of hydrogen and carbon has been developed. Using the modification of the Wittig reaction introduced by E. J. Corey, in which a solution of the methylsulfinyl carbanion in dimethyl sulfoxide serves as the base, a series of olefins from C2 to C8 were synthesized. The synthesis was applied to the preparation of the following labelled compounds: 5-methylene-14C-bicyclo[2.2.1]hept-2-ene; propene-1-14C; 1-butene-1-14C; propene-1-d1; 2-methylpropene-1,1-d2; 2-methyl-d3-propene-3,3,3-d3; 2-methyl-2-butene-4,4,4-d3; 2-methyl-d3-2-butene-1,1,1-d3; methylene-d2-cyclohexane. For the synthesis of carbon-labelled olefins the reaction has few limitations since the intermediates and products are isotopically stable under the reaction conditions. Deuterium-labelled olefins can be obtained from deuterated formaldehyde or β-deuterated phosphonium salts, but α-deuteroketones and aldehydes and α-deuterophosphonium salts lose the isotope to the solvent.In all the Wittig reactions, benzene was formed as a by-product in 10–15% yield. The mechanism of benzene formation is probably analogous to that proposed by Seyferth involving the decomposition of a pentacovalent phosphorous intermediate.

Synthesis of δ-Ketonic and δ-Thioacetalated Phosphonium Salts and Their Use in Wittig Reactions for Carbonyl n + 4 Homologation

Synthesis ◽  
1987 ◽  
Vol 1987 (07) ◽  
pp. 648-651 ◽  
Author(s):  
Henri-Jean Cristau ◽  
Yves Beziat ◽  
Claude Ekissi Niangoran ◽  
Henri Christol
Keyword(s):  
Phosphonium Salts ◽  
Wittig Reactions

Highly functionalized alkenes produced from base-free organocatalytic Wittig reactions: (E)-3-benzylidenepyrrolidine-2,5-dione, (E)-3-benzylidene-1-methylpyrrolidine-2,5-dione and (E)-3-benzylidene-1-tert-butylpyrrolidine-2,5-dione

2016 ◽  
Vol 72 (6) ◽  
pp. 504-508 ◽  
Author(s):  
Marie-Luis Schirmer ◽  
Anke Spannenberg ◽  
Thomas Werner
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Carbonyl Compounds ◽  
Wittig Reaction ◽  
Phosphonium Salts ◽  
Asymmetric Unit ◽  
Free Base ◽  
Fundamental Transformation ◽  
Wittig Reactions ◽  
Centrosymmetric Dimers

The Wittig reaction is a fundamental transformation for the preparation of alkenes from carbonyl compounds and phosphonium ylides. The ylides are prepared prior to the olefination step from the respective phosphonium salts by deprotonation utilizing strong bases. A first free-base catalytic Wittig reaction for the preparation of highly functionalized alkenes was based on tributylphosphane as the catalyst. Subsequently we developed a system employing a phospholene oxide as a pre-catalyst and trimethoxysilane as reducing agent which operates under milder conditions. The title compounds, (E)-3-benzylidenepyrrolidine-2,5-dione, C11H9NO2, (I), the methylpyrrolidine derivative, C12H11NO2, (II), and thetert-butylpyrrolidine derivative, C15H17NO2, (III), have been synthesized by base-free catalytic Wittig reactions. In the crystal of (I), molecules are linked into centrosymmetric dimersviapairs of N—H...O hydrogen bonds. Furthermore, in the crystal structure of (III), there are two molecules in the asymmetric unit, whereas in (I) and (II), only one molecule is present.

ChemInform Abstract: Synthesis and Aza-Wittig Reactions of Cyclic Amino Phosphonium Salts.

ChemInform ◽  
2010 ◽  
Vol 26 (23) ◽  
pp. no-no
Author(s):  
T. SAKAI ◽  
T. KODAMA ◽  
T. FUJIMOTO ◽  
K. OHTA ◽  
I. YAMAMOTO ◽  
...  
Keyword(s):  
Phosphonium Salts ◽  
Wittig Reactions
Sign in / Sign up

Export Citation Format

Share Document