- trans-Stereoselective intramolecular crossed pinacol coupling of aromatic 1,4-, 1,5-, and 1,6-diketones by electroreduction
-
Electroreduction of aromatic 1,4-, 1,5-, and 1,6-diketones in the presence of chlorotrimethylsilane and triethylamine gave four-, five-, and six-membered 1,2-diols with trans-stereoselectivity.
- Kise, Naoki,Shiozawa, Yousuke,Ueda, Nasuo
-
-
Read Online
- Cyclopentane Formation from Flexible Precursors Using Samarium(II) Reagents
-
Three efficient methods for five-membered ring carbocycle synthesis have been developed from simple starting materials using samarium(II) reagents. A Reformatsky aldol reaction proceeded efficiently with samarium(II) iodide using lithium bromide as an additive. A new intramolecular alkylation of a samarium enolate was realized with a pendant sulfonate ester leaving group. Pinacol cyclization of a simple diketone was also demonstrated giving a diol product in high stereoselectivity. A promising lead result has been established demonstrating enantioselectivity in a chiral ligand controlled Reformatsky aldol reaction.
- Aretz, Christopher D.,Escobedo, Humberto,Cowen, Bryan J.
-
supporting information
p. 1880 - 1884
(2018/05/09)
-
- Unexpected TiIII/Mn-promoted pinacol coupling of ketones
-
Titanocene(III) chemistry has emerged in the last decades as an indispensable tool in C-C bond-forming reactions. In this context, pinacol and related reactions allow the stereoselective synthesis of vicinal diols. In this work, we present new applications of these reactions using as starting materials aromatic ketones. Simple and smooth reaction conditions have been developed and have been applied for inter- and intramolecular processes. We also describe that although Cp2TiCl is usually used as a monoelectronic reducing agent, it can be also used as an efficient Lewis acid.
- Paradas, Miguel,Campana, Araceli G.,Estevez, Rosa E.,De Cienfuegos, Luis Alvarez,Jimenez, Tania,Robles, Rafael,Cuerva, Juan M.,Oltra, J. Enrique
-
experimental part
p. 3616 - 3619
(2009/09/06)
-
- Electroreductive crossed pinacol coupling of aromatic ketones with aliphatic ketones and aldehydes
-
The intermolecular crossed pinacol coupling of aromatic ketones with aliphatic aldehydes and ketones was effected by electroreduction in the presence of chlorotrimethylsilane. The best result was obtained using a Pb cathode in Bu4NPF6/sub
- Kise, Naoki,Shiozawa, Yousuke,Ueda, Nasuo
-
p. 5415 - 5426
(2008/01/07)
-
- Oxidative Cleavage of vic-Diols Using Copper(II) Bromide-Lithium t-Butoxide: A New Route to Unsymmetrical 1,5- and 1,6-Diketones
-
Unsymmetrical 1,6-diketones were obtained by the copper(II) bromide-lithium t-butoxide oxidation of 1,2-disubstituted 1,2-cyclohexanediols. The diols were easily prepared by the addition of Grignard reagents to 2-trimethylsiloxy-2-cyelohexenone followed by the hydrolysis and treatment of the resulting 2-hydroxycyclohexanones with the second Grignard reagents. Similarly, 1,5-Diketones were obtained using 2-trimethylsiloxy-2-cyclopentenone as a starting material.
- Fujiwara, Tooru,Tsuruta, Yumiko,Arizono, Ko-Ichi,Takeda, Takeshi
-
p. 962 - 964
(2007/10/03)
-