TI(III) oxidation of alkenes and alkynes and Ru(III) catalysis in the oxidation of alkenes: A kinetic and mechanistic study

Abstract

The oxidation of trans-stilbene, phenylacetylene, and diphenylacetylene by TI(0Ac)s in aqueous acetic acid medium in the presence of HC104 follows the rate law The formation constants K for the Ru(II1)-alkene a complex at 40,50, and 60°C are 90.14M-', 105.2M-l, and 127.7M-l, respectively. Interestingly the oxidation of phenylacetylene and diphenylacetylene does not undergo catalysis by Ru(II1). The mechanism involving the metal-arene K complex is discussed.

N-Halosuccinimide/BF3−H2O, Efficient Electrophilic Halogenating Systems for Aromatics

“…Incorporation of iodine into the aromatic ring is achieved by indirect methods such as the Sandmeyer reaction. NIS activated by acids (including trifluoromethanesulfonic acid) in catalytic or stoichiometric quantities has been found to be useful for electrophilic iodinations. ,− Because the acidity of boron trifluoride monohydrate, as discussed, is close to that of trifluoromethanesulfonic acid (− H o = 14.1), NIS/BF 3 −H 2 O reagent was found suitable to achieve direct iodination of deactivated aromatics such as nitrobenzene under mild conditions. The reactions usually were faster than bromination, and only minor amounts of diiodinated products were observed in some cases.…”