Wittig Reactions in Water Media Employing Stabilized Ylides with Aldehydes. Synthesis of α,β-Unsaturated Esters from Mixing Aldehydes, α-Bromoesters, and Ph<sub>3</sub>P in Aqueous NaHCO<sub>3</sub>
作者:Amer El-Batta、Changchun Jiang、Wen Zhao、Robert Anness、Andrew L. Cooksy、Mikael Bergdahl
DOI:10.1021/jo070665k
日期:2007.7.1
range of stabilized ylides and aldehydes. Despite sometimes poor solubility of the reactants, good chemical yields normally ranging from 80 to 98% and high E-selectivities (up to 99%) are achieved, and the rate of the reactions in water is unexpectedly accelerated. The efficiency of water as a medium in the Wittig reaction is compared to conventional organic solvents ranging from carbon tetrachloride
N,N,N′,N′-Tetramethylenediamine dioxide (TMEDAO<sub>2</sub>) facilitates atom economical/open atmosphere Ley–Griffith (TPAP) tandem oxidation-Wittig reactions
作者:Christopher D. G. Read、Peter W. Moore、Craig M. Williams
DOI:10.1039/c5gc01346a
日期:——
N,N,N′,N′-Tetramethylethylenediamine dioxide (TMEDAO2) was explored as a more atom economical co-oxidant for the Ley–Griffith oxidation of alcohols to aldehydes.
N, N, N′, N′-四甲基乙二胺二氧化物(TMEDAO2)被探讨作为 Ley–Griffith 氧化醇制醛反应中更具原子经济性的辅助氧化剂。
An expedient stereoselective synthesis of ( E )- α,β -unsaturated esters and thioesters using FeCl 3 ·6H 2 O
作者:Amar R. Mohite、Trimbak B. Mete、Ramakrishna G. Bhat
DOI:10.1016/j.tetlet.2017.01.024
日期:2017.2
Facile and convenient synthesis of α,β-unsaturatedesters and thioesters from alkylidene derivatives of Meldrum’s Acid is described. This method uses catalytic amount of FeCl3·6H2O (0.001–0.005 equiv) with alcohols/thiols (1 equiv) in dry CH3NO2 followed by catalytic amount of piperidine. A variety of α,β-unsaturatedesters and thioesters have been synthesized with high E-stereoselectivity in good
描述了从Meldrum's Acid的亚烷基衍生物容易且方便地合成α,β-不饱和酯和硫代酯。该方法在干燥的CH 3 NO 2中使用催化量的FeCl 3 ·6H 2 O(0.001-0.005当量)与醇/硫醇(1当量),然后催化量的哌啶。已经以高至优异的产率合成了具有高E-立体选择性的多种α,β-不饱和酯和硫代酯。该方法的应用通过辛辛酸,防晒剂和其他对甲氧基肉桂酸酯的克规模合成得到证明。
Catalytic, Enantioselective β-Protonation through a Cooperative Activation Strategy
作者:Michael H. Wang、David Barsoum、C. Benjamin Schwamb、Daniel T. Cohen、Brian C. Goess、Matthias Riedrich、Audrey Chan、Brooks E. Maki、Rama K. Mishra、Karl A. Scheidt
DOI:10.1021/acs.joc.7b00334
日期:2017.5.5
only feasible, but also adaptable to a kinetic resolution of secondaryalcohols through NHC-catalyzed acylation. In-depth analysis of this process determined that careful catalyst and solvent pairing is critical for optimal yield and selectivity; proper choice of nonpolar solvent provided improved yield through suppression of an oxidative side reaction, while employment of a cooperative catalytic approach