Oxidation of various cyclic and acyclic ketones under mild conditions with chlorocatecholborane, a bulky pyridine base, and TEMPO to the corresponding α-aminoxylated products in good to excellent yields (52–99%) is described. For enones as substrates, products of a β-chloro-α-aminoxylation are obtained (70–89%).
Under blue-light irradiation conditions with a photocatalyst [1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene], silyl enol ethers reacted with alkenes in the presence of a smallamount of water to afford the α-alkylation products in good to high yields. A thiol cocatalyst was found to expand the substrate scope of the reaction.
Facile and Highly Diastereoselective Synthesis of<i>syn</i>- and<i>cis</i>-1,2-Diol Derivatives from Protected α-Hydroxy Ketones
作者:Emanuela Jahn、Jakub Smrček、Radek Pohl、Ivana Císařová、Peter G. Jones、Ullrich Jahn
DOI:10.1002/ejoc.201501174
日期:2015.12
method for the synthesis of monoprotected syn- or cis-1,2-diol derivatives by reduction of easily accessible α-(2,2,6,6-tetramethylpiperidinyloxy) ketones is reported. The α-(tetramethylpiperidinyloxy) group as the stereodirecting group induces in unhindered acyclic or cyclic ketones complete syn- or cis-diastereoselectivity, respectively, with L-Selectride. For more hindered derivatives, where L-Selectride
Copper-Catalyzed Aminoxylation of Different Types of Hydrocarbons with TEMPO: A Concise Route to<i>N-</i>Alkoxyamine Derivatives
作者:Linyi Li、Zhengwei Yu、Zengming Shen
DOI:10.1002/adsc.201500544
日期:2015.11.16
An efficient copper(II)/tert-butyl hydroperoxide catalyst system [(Bpy)Cu(II)/TBHP] for the aminoxylation of different types of hydrocarbons under mild and ambient air conditions has been developed to furnish N-alkoxyamine derivatives in good to high yields. Ketones, esters, nitriles, toluene, ethylbenzene, heterocycles, cyclohexene, and cyclohexanes are well compatible in this system and the catalyst
Organocatalysis in Radical Chemistry. Enantioselective α-Oxyamination of Aldehydes
作者:Mukund P. Sibi、Masayuki Hasegawa
DOI:10.1021/ja069245n
日期:2007.4.1
We have developed an efficient radical α-oxyamination reaction using chiral organocatalysts. The reaction can be carried out with inexpensive SET reagents, and a reasonably broad substrate scope has been established. Good to high enantioselectivity for the α-oxygenated products are obtained using 20 mol % of the catalyst. The methodology reported in this work adds to the repertoire of asymmetric radical
我们开发了一种使用手性有机催化剂的高效自由基 α-氧胺化反应。该反应可以使用廉价的 SET 试剂进行,并且已经建立了相当广泛的底物范围。使用 20 mol% 的催化剂可以获得良好到高的 α-氧化产物的对映选择性。这项工作中报道的方法增加了可以使用有机催化剂进行的不对称自由基反应的全部内容。