Diazo Reagents in Copper(I)-Catalyzed Olefination of Aldehydes
作者:Hélène Lebel、Michaël Davi
DOI:10.1002/adsc.200800381
日期:2008.10.6
The olefination of aldehydes to synthesize unsaturated ketones, esters, amides and phosphonates using diazo reagents and triphenylphosphine in the presence of copper(I) iodide as catalyst, is described. Good to excellent E:Z selectivities as well as yields were obtained for a large variety of aliphatic, aromatic and heteroaromatic aldehydes. The reaction showed also an excellent functional group compatibility
Generation of Phosphoranes Derived from Phosphites. A New Class of Phosphorus Ylides Leading to High <i>E</i> Selectivity with Semi-stabilizing Groups in Wittig Olefinations
作者:Varinder K. Aggarwal、J. Robin Fulton、Chris G. Sheldon、Javier de Vicente
DOI:10.1021/ja029573x
日期:2003.5.1
Tosylhydrazones derived from aryl aldehydes react with t-BuOK, ClFeTPP, (MeO)3P, and aldehydes to furnish olefins with high E selectivity. These reactions occur through a Wittig-type pathway via the corresponding diazo compounds, metal carbenes and phosphorous ylides, with the water-soluble trimethyl phosphate as the byproduct. Similar reactions can also be performed using ethyl diazoacetate; however
源自芳基醛的甲苯磺酰腙与 t-BuOK、ClFeTPP、(MeO)3P 和醛反应以提供具有高 E 选择性的烯烃。这些反应通过相应的重氮化合物、金属卡宾和磷叶立德通过 Wittig 型途径发生,副产物为水溶性磷酸三甲酯。使用重氮乙酸乙酯也可以进行类似的反应;然而,仅在 LiBr 存在下才观察到高 E 选择性。在这种情况下,该反应被认为是通过通过 Arbuzov 反应形成的膦酸阴离子发生的。因此,该烯化反应通过 Horner-Wadsworth-Emmons (HWE) 反应发生,但膦酸阴离子是在完全无碱的条件下生成的。
Olefination of aldehydes by ethyl diazoacetate catalyzed by a ruthenium(II) complex
作者:Osamu Fujimura、Takashi Honma
DOI:10.1016/s0040-4039(97)10661-x
日期:1998.2
A variety of aldehydes were stereoselectively converted to (E)-olefins by the reaction with ethyldiazoacetate and triphenylphosphine in the presence of a catalytic amount of RuCl2(PPh3)3
Tandem Palladium and Isothiourea Relay Catalysis: Enantioselective Synthesis of α-Amino Acid Derivatives via Allylic Amination and [2,3]-Sigmatropic Rearrangement
作者:Stéphanie S. M. Spoehrle、Thomas H. West、James E. Taylor、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1021/jacs.7b05619
日期:2017.8.30
has been developed for the enantioselective synthesis of α-aminoacid derivatives containing two stereogenic centers from readily accessible N,N-disubstituted glycine aryl esters and allylic phosphates. The optimized process uses a bench-stable succinimide-based Pd precatalyst (FurCat) to promote Pd-catalyzed allylic ammonium salt generation from the allylic phosphate and the glycine aryl ester. Subsequent
Facile synthesis of α, β-unsaturated esters through a one-pot copper-catalyzed aerobic oxidation-Wittig reaction
作者:Cheng Ren、Zhenyu Shi、Weijie Ding、Zhiqing Liu、Huile Jin、Xiaochun Yu、Shun Wang
DOI:10.1016/j.tetlet.2017.09.020
日期:2018.1
An efficient one-pot synthesis of α, β-unsaturated estersthrough the aerobic oxidation – Wittig tandem reaction of alcohols and phosphorous ylide is developed. This new method operates under mild reaction conditions, and uses CuI/TEMPO (TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) as co-catalyst and air (O2) as the oxidant. It tolerates a wide range of functionalized benzylic alcohol and aliphatic