Bulky phosphonate and ester substituents enhance (E)-selectivity in disubstituted olefin synthesis. The steric bulk of the phosonate and electron-withdrawing groups plays a critical role in the reaction ofphosphonates with aliphatic aldehydes.
(metatrajectory)shows the early formation of the C-C bond followed by the P-0 bonding formation and simultaneous breaking of the P-C and C-O bond.Within this process,a high E selectivity for all ylides is observed.The metadynamics analysis encompasses all possible energy reaction coordinates;...
It has been observed that ultimate configuration of olefins depends on many factors, such as the structure of phosphoranes, the base and the solvent used, the concentration of ylide, and the reaction temperature. In particular, the Z -selectivity from nonstabilized ylides can be further enhanced...
The Wittig reaction of stabilized ylides with aldehydes proceeds under the conditions of kinetic control. (E)-Selectivity results from selective formation of trans-oxaphosphetanes. The presence of electron-withdrawing substituents destabilizes the intermediary products and accelerates the decomposition of ...
稳定膦Ylide在水相中的Wittig反应 浙江大学 硕士学位论文 稳定膦Ylide在水相中的Wittig反应 姓名：张达 申请学位级别：硕士 专业：有机化学 指导教师：吴金龙 20040301
4、ynthesisischemistshavebeenpursuingthegoal.WiththediscoveryoftheWittigreaction,whichhastheadvantagesofhighreactionyield,mildreactioncondition,highpositionselectivity,andsoon,itiswidelyusedinthesynthesisoffinechemicals.IsintroducedinthispaperWittigreactionanditsdevelopmentprocessimprovement,basedoncla ...
Reactionistheoneofusefulreactionfororganicsynthesisandwidevarietyofapplicationshavebeenreported.[1]ThisreactioncanconvertaC=Odoublebond,suchasaldehydesorketones,toaC=Cdoublebondusingavariousphosphorusylidereagentwithgoodstereoselectivity.Incaseofthetwosubstitutentalkeneisobtained,highselectivityforZ-orE-olefinsisavailable...
The (E)/(Z) selectivity is often poor by employing semi-stabilized ylides (R3 = aryl).3 Thus, since its discovery, Wittig reaction has frequently and extensively used in the predictable and selective formation of the (Z)-alkenes, thus employed as a key step (steps) in the total ...
thepositionofdoublebondinolefinsisexactlythepo—sitionofcarbonylgroupinthereactants,sotherearenootherpositionisomersinproducts.Duetothisadvantage,Wittingreactionhasbeenwidelyusedinorganicsynthesis….Wittingreactioncouldintroducedoublebondtocertainpositionaccurately.Besides,italsohasstereOselectivitv'f.e.,upondifferent...
catalytic arsa-Wittig reactiondensity functional calculationsE/Z selectivityiron-freedoi:10.1002/chem.202004074Inaba, RyotoKawashima, IkuoFujii, ToshikiYumura, TakashiImoto, HiroakiNaka, KensukeJohn Wiley & Sons, LtdChemistry - A European Journal