223243-87-6Relevant academic research and scientific papers
Mild zinc-promoted Horner-Wadsworth-Emmons reactions of diprotic phosphonate reagents
Schauer, Douglas J.,Helquist, Paul
, p. 3654 - 3660 (2008/03/13)
We report the development of a mild protocol for the Horner-Wadsworth- Emmons reaction of diprotic phosphonates that makes use of a zinc triflate promoter in the presence of mild ter-tiary amine bases to produce α,β-unsaturated carboxylic acids and amides. Georg Thieme Verlag Stuttgart.
Direct reaction of dibromoacetic acid with aldehydes promoted by samarium diiodide: An easy, efficient, and rapid synthesis of (E)-α,β- unsaturated carboxylic acids with total stereoselectivity
Concellon, Jose M.,Concellon, Carmen
, p. 1728 - 1731 (2007/10/03)
A promoted SmI2 direct reaction of dibromoacetic acid with different aldehydes, followed by an elimination reaction also promoted by samarium diiodide, affords (E)-α,β-unsaturated carboxylic acids 2 with total stereoselectivity. A mechanism to explain this transformation is proposed.
Meta, para and ortho double exo nucleophilic additions of trimethylsilylester enolates derived from saturated and unsaturated carboxylic acids to tricarbonylchromium complexes of aryl ethers: dearomatizing cyclization to lactones
Rudler, Henri,Comte, Virginie,Garrier, Eva,Bellassoued, Moncef,Chelain, Evelyne,Vaissermann, Jaqueline
, p. 284 - 298 (2007/10/03)
Potassium enolates derived from saturated and unsaturated bis(trimethylsilyl) ketene acetals react with tricarbonylchromium complexes of anisole and diphenylether to give, in addition to α-arylcarboxylic acids, the mono addutcts, lactones, arising from a double exo nucleophilic addition. The latter were not observed in the case of benzenetricarbonylchromium. The intermediate dienol ethers could be isolated and fully characterized by X-ray crystallography. The influenece of the nature of the substituents on the ketene acetals, of the nature of the oxidant, and of the nature of the ester enolates on the course of the reaction has been established and will be discussed.
(E)-Selective hydrolysis of (E,Z)-α,β-unsaturated nitriles by the recombinant nitrilase AtNIT1 from Arabidopsis thaliana
Effenberger, Franz,Osswald, Steffen
, p. 2581 - 2587 (2007/10/03)
From stereoisomeric α,β-unsaturated nitriles (E,Z)-1, the recombinant nitrilase AtNIT1 from Arabidopsis thaliana hydrolyses the (E)-isomers exclusively to the corresponding (E)-carboxylic acids (E)-2 with high specificity. The (E)-selectivity can also be utilised for the preparation of the isomerically pure nitriles (Z)-1. From (E,Z)-2-hydroxycinnamonitrile (E,Z)-3, the otherwise difficult obtainable (Z)-3 was prepared in 66% isolated yield. With β,γ-unsaturated (E,Z)-3-heptenenitrile (E,Z)-4, however, (E)-selectivity was not observed. AtNIT1 exhibits not only diastereoselectivity but also regioselectivity. From a mixture of the four isomers A-D of 3-(2-cyanocyclohex-3-enyl)propenenitrile 6, exclusively isomer D ((E)-cis-6) was hydrolysed to 3-(2-cyanocyclohex-3-enyl)propenoic acid (E)-cis-7, as stated by X-ray crystal structure. Only after complete conversion of D and high enzyme concentrations, isomer C ((E)-trans-6) was hydrolysed to a small extent.
SiO2 catalysed expedient synthesis of [E]-3-alkenoic acids in dry media
Kumar, H.M. Sampath,Reddy, B.V. Subba,Reddy, E. Jagan,Yadav
, p. 2401 - 2404 (2007/10/03)
Aliphatic aldehydes with α-hydrogens and malonic acid undergo decarboxylative condensation on the surface of SiO2 when subjected to microwave irradiation generating βγ-unsaturated acids in high yields.
