Efficient Conversion of Ketones to α-Tosyloxyketones with <i>m</i>-Chloroperbenzoic Acid and <i>p</i>-Toluenesulfonic Acid in the Presence of Catalytic Amount of IL-Supported PhI in [emim]OTs
作者:Hideo Togo、Junnosuke Akiike、Yukiharu Yamamoto
DOI:10.1055/s-2007-984914
日期:——
Various ketones were smoothly converted into the corresponding α-tosyloxyketones with MCPBA and p-toluenesulfonic acid in the presence of a catalytic amount of ionic-liquid (IL)-supported PhI in room temperature ionic liquid, [emim]OTs. Moreover, the present ionic-liquid reaction media containing a catalytic amount of IL-supported PhI could be reused for the same α-tosyloxylation of ketones and thiazoles directly, keeping good yields.
Iodoarene-Mediated α-Tosyloxylation of Ketones with MCPBA and p-Toluenesulfonic Acid
作者:Hideo Togo、Ayumi Tanaka、Katsuhiko Moriyama
DOI:10.1055/s-0030-1260948
日期:2011.8
Alkyl aryl ketones and dialkyl ketones could be converted into the corresponding α-tosyloxy ketones by the reaction with MCPBA and p-toluenesulfonic acid monohydrate (PTSAËH2O) in the presence of a catalytic amount of molecular iodine (I2) in a mixture of acetonitrile and 2,2,2-trifluoroethanol, although the yields were dependent on the ketones (method A). The same conversion of alkyl aryl ketones and dialkyl ketones into the corresponding α-tosyloxy ketones could be smoothly carried out by the reaction with MCPBA and PTSAËH2O in the presence of catalytic amounts of iodine and tert-butylbenzene in a mixture of acetonitrile and 2,2,2-trifluoroethanol (method B). In those reactions, p-iodotoluene and 4-tert-butyl-1-iodobenzene were formed at first in method A and method B, respectively, and then they were converted into p-[(hydroxy)(tosyloxy)]iodotoluene and 4-tert-butyl-1-[(hydroxy)(tosyloxy)iodo]benzene by the reaction with MCPBA and PTSAËH2O. p-[(Hydroxy)(tosyloxy)]iodotoluene and 4-tert-butyl-1-[(hydroxy)-(tosyloxy)iodo]benzene worked as an α-tosyloxylation reagent of ketones.
4-MeC6H4I-Mediated Efficient α-Tosyloxylation of Ketones with Oxone® and p-Toluenesulfonic Acid in Acetonitrile
作者:Hideo Togo、Ayumi Tanaka
DOI:10.1055/s-0029-1218370
日期:2009.12
Various alkyl aryl ketones, dialkyl ketones, and cycloheptanone were efficiently converted into the corresponding α-tosyloxy ketones in good yields by using Oxone® and p-toluenesulfonic acid monohydrate in the presence of p-iodotoluene in acetonitrile. 4-Methoxyacetophenone and 2-acetylthiophene bearing an electron-rich aromatic group could be also converted into the corresponding α-tosyloxyketones smoothly in good yields with the present method. Here, p-iodotoluene works as catalyst and p-[(hydroxy)(tosyloxy)]iodotoluene is formed in situ as a reactive species for the α-tosyloxylation of ketones. However, one equivalent of p-iodotoluene was required to obtain α-tosyloxyketones in good yields and was recovered in 80-20% yields, depending on the reaction conditions.
Novel Preparation of Polymer-Supported Iodobenzene and Its Synthetic Utility as a Recyclable Reagent with m-Chloroperbenzoic Acid
作者:Hideo Togo、Yuhsuku Suzuki
DOI:10.1055/s-0029-1218795
日期:2010.7
Three novel polymer-supported iodobenzene compounds A0, A6, and A10 were prepared from the reaction of commercially available cross-linked poly(p-chloromethyl)styrene with m-iodobenzylalcohol, 6-(m-iodobenzyloxy)-1-hexanol, and 10-(m-iodobenzyloxy)-1-decanol. Their catalytic reactivity and reusability for the oxidative α-tosyloxylation of ketones and the cyclization of N-methoxy-2-arylethanesulfonamides