- Transformation of α,β-epoxyesters into 2,3-dideuterioesters promoted by samarium diiodide
-
An easy and general sequenced elimination/reduction process by means of samarium diiodide, in the presence of D2O, provides an efficient method for synthesizing 2,3-dideuterioesters 2. The reaction can be also carried out in the presence of H2O instead of D2O, yielding the corresponding saturated esters 4. Other deuterated esters have been also obtained. A mechanism to explain this synthesis has been proposed.
- Concellon, Jose M.,Bardales, Eva,Llavona, Ricardo
-
p. 1585 - 1588
(2007/10/03)
-
- Synthesis of (E)-α,β-unsaturated esters with total or high diastereoselectivity from α,β-epoxyesters
-
Chemical equation presented High stereoselective β-elimination in 2,3-epoxyesters 1 was achieved using samarium diiodide, yielding α,β-unsaturated esters 2, in which the C=C bond is di-, tri- or tetrasubstituted. The starting compounds 1 are easily prepared by reaction of the corresponding lithium enolates of a-chloroesters with aldehydes or ketones at -78 °C. The influence of the reaction conditions and the structure of the starting compounds in the stereoselectivity of the β-elimination reaction is also discussed.
- Concellon, Jose M.,Bardales, Eva
-
p. 189 - 191
(2007/10/03)
-
- MASS SPECTROMETRIC DECOMPOSITION OF β-PHENYLOXIRANECARBOXYLIC ESTERS
-
The electron-impact mass spectra of the E- and Z-isomers of the α,β-methyl substituted esters of β-phenyloxiranecarboxylic acids have been studied.
- Anisimova, O. S.,Chistyakov, V. V.,Bokanov, A. I.,Shvedov, V. I.,Sheinker, Yu. N.
-
p. 1058 - 1063
(2007/10/02)
-
- STEREOSPECIFITY OF THE SPIN-SPIN COUPLING CONSTANTS AND CHEMICAL SHIFTS IN THE 13C NMR SPECTRA OF OXIRANECARBOXYLIC ESTERS
-
It was established that the 3JCH spin-spin coupling constants and chemical shifts in the 13C NMR spectra of the cis and trans isomers of oxiranecarboxylic esters are stereospecific.The signals for the methyl groups of the cis isomer are 4-7 ppm upfield from the signals for the trans isomer.The 3JCH constant due to spin-spin coupling of the 2-CH3 (or 3-CH3) group and the proton at the C3 (or C2) atom amounts to 2 Hz for the cis isomer and is absent for the trans isomer.
- Alekseeva, L. M.,Bokanov, A. I.,Shvedov, V. I.,Sheinker, Yu. N.
-
p. 1664 - 1666
(2007/10/02)
-