72284-20-9Relevant articles and documents
Asymmetric cyclopentannelation. Chiral auxiliary on the allene
Harrington, Paul E.,Tius, Marcus A.
, p. 2447 - 2450 (2000)
(equation presented) An enantioselective variant of the synthesis of cross-conjugated cyclopentenones, based on D-glucose-derived chiral auxiliaries, is described. Minor modification of the method makes it applicable to the preparation of both enantiomeri
Scalable Preparation of Methylated Ando-Type Horner-Wadsworth-Emmons Reagent
Bressin, Robert K.,Driscoll, Julia L.,Wang, Yanping,Koide, Kazunori
, p. 274 - 277 (2019/02/14)
The Horner-Wadsworth-Emmons (HWE) reactions are vital to the chemical synthesis of complex molecules, forging a carbon-carbon double bond in the generation of α,β-unsaturated enoates from aldehydes or ketones. Despite their frequent use, the Z-stereoselective formation of α,β-unsaturated esters from aldehydes have been mostly limited to the use of the commercially available Still-Gennari reagent. Ando developed an alternative reagent to achieve the same formation with less expensive reagents. However, an α-methylated Ando-HWE reagent has remained difficult to prepare, hindering a reliable route to α,β-disubstituted Z-enoates. Here, we report the development of a preparative synthesis of a methylated Ando-HWE reagent for the highly Z-selective HWE reaction. Costing $0.49/mmol, this synthesis is significantly cheaper than the currently available Still-Gennari reagent ($11/mmol, Millipore Sigma 2018). The purification procedure does not require chromatography, with recrystallization as the only purification method, making it highly amenable to large-scale production.
A convenient synthesis of (E)-α,β-unsaturated esters with total stereoselectivity promoted by catalytic samarium diiodide
Concellón, José M.,Rodríguez-Solla, Humberto,Concellón, Carmen,Díaz-Pardo, Ainhoa,Llavona, Ricardo
experimental part, p. 262 - 264 (2011/03/21)
Synthesis of (E)-α,β-unsaturated esters in high yields and with total stereoselectivity is achieved from α-halo-β-hydroxy esters promoted by catalytic amounts of SmI2. The starting compounds were easily prepared from α-halo esters and aldehydes as a mixture of stereoisomers. A mechanism is proposed to explain this samarium(II)-promoted catalytic β-elimination reaction. Georg Thieme Verlag Stuttgart.
