نتایج جستجو برای: 3 ketoesters

تعداد نتایج: 1811529  

2006
Marko D. Mihovilovic Thomas C. M. Fischer Peter Stanetty

We present an easy method for the synthesis of β-ketoesters starting from various carbocyclic and heterocyclic carboxylic acids and esters. The β-ketoester side-chain was introduced by a sequence involving α-deprotonation and quenching with CO2, conversion to the corresponding acid chloride and subsequent chain elongation using deprotonated ethyl acetate.

Journal: :Chemical communications 2005
Carole Foltz Björn Stecker Guido Marconi Stéphane Bellemin-Laponnaz Hubert Wadepohl Lutz H Gade

Chiral C3-symmetric trisoxazolines are highly efficient stereodirecting ligands in enantioselective Cu(II) Lewis acid catalysis which is based on the concept of a stereoelectronic hemilability of the divalent copper; in direct comparison with the analogous bisoxazoline systems they are more efficient in the enantioselective alpha-amination as well as the enantioselective Mannich reaction of pro...

Journal: :Journal of the American Chemical Society 2004
Joshua J Kennedy-Smith Steven T Staben F Dean Toste

The intramolecular addition of beta-ketoesters to unactivated alkynes under neutral conditions and at room temperature is described. The method employs triphenylphosphinegold(I) cation as a catalyst for the formation of exo-methylenecycloalkanes. Both monocyclic and bicyclic cyclopentanes and cyclohexanes can be formed in excellent yields and with good diastereoselectivity.

2012
Wen-Bin Yi Xin Huang Zijuan Zhang Dian-Rong Zhu Chun Cai Wei Zhang

A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from the reaction mixture by simple fluorous solid-phase extraction (F-SPE) and used for the next round of reaction without further purification.

Journal: :Molecules 2011
Yasunori Yamamoto Tomohiko Shirai Momoko Watanabe Kazunori Kurihara Norio Miyaura

A ruthenium-catalyzed asymmetric arylation of aliphatic aldehydes and α-ketoesters with arylboronic acids has been developed, giving chiral alkyl(aryl)methanols and α-hydroxy esters in good yields. The use of a chiral bidentate phosphoramidite ligand (Me-BIPAM) achieved excellent enantioselectivities.

Journal: :Journal of the American Chemical Society 2005
David A Evans Daniel Seidel

A highly enantioselective Michael addition of 1,3-dicarbonyl compounds to nitroalkenes has been developed that employs a newly developed Ni(II)-(bis)diamine based catalyst. The reaction scope includes substituted and unsubstituted malonates, beta-ketoesters, and nitroalkenes bearing aromatic and aliphatic residues. Ease of synthesis of this complex is noteworthy.

In this research, a Brønsted acidic ionic liquid namely N1,N1,N2,N2-tetramethyl-N1,N2-bis(sulfo)ethane-1,2-diaminium chloride {[TMBSED][Cl]2} was employed as a highly efficient catalyst for the solvent-free production of some nitrogen- and oxygen-containing heterocyclic compounds including: (i) polyhydroquinolines (from arylaldehydes, dimedone, β-ketoesters and ammonium acetate), (ii) 3,4-dihyd...

2014
Yiwen Xiong Haibo Mei Lingmin Wu Jianlin Han Yi Pan Guigen Li

A variety of chiral N-phosphinyl α-imino esters have been synthesized for the first time from ketoesters and phosphinylamide, which were then reduced by L-selectride to give the corresponding N-phosphinyl-protected α-amino esters. The reduction proceeded very well with excellent chemical yields (88-98%) as well as high diastereoselectivities (96:4 to 99:1). Some of these products could be obtai...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید