Iodoarene-Mediated α-Tosyloxylation of Ketones with MCPBA and p-Toluenesulfonic Acid

Abstract

Alkyl aryl ketones and dialkyl ketones could be converted intothe corresponding α-tosyloxy ketones by the reaction with MCPBAand P-toluenesulfonic acid monohydrate(PTSA˙H 2 O) in the presence of a catalytic amountof molecular iodine (I 2 ) in a mixture of acetonitrileand 2,2,2-trifluoroethanol, although the yields were dependent onthe ketones (method A). The same conversion of alkyl aryl ketonesand dialkyl ketones into the corresponding α--tosyloxyketones could be smoothly carried out by the reaction with MCPBAand PTSA˙H 2 O in the presence of catalytic amountsof -iodine and TERT-butylbenzenein a mixture of acetonitrile and 2,2,2-trifluoroethanol (methodB). In those reactions, P-iodotolueneand 4- TERT-butyl-1-iodobenzene were formedat first in method A and method B, respectively, and then they wereconverted into P-[(hydroxy)(tosyloxy)]iodotolueneand 4- TERT-butyl-1-[(hydroxy)(tosyloxy)iodo]benzeneby the reaction with MCPBA and PTSA˙H 2 O. P-[(Hydroxy)(tosyloxy)]iodotolueneand 4- TERT-butyl-1-[(hydroxy)-(tosyloxy)iodo]benzeneworked as an α-tosyloxylation reagent of ketones.