Toshiyuki Moriuchi
Osaka University, Japan
Title: Vanadium-catalyzed bromination reaction with molecular oxygen
Biography
Biography: Toshiyuki Moriuchi
Abstract
Bromination of organic compounds is one of the most fundamental reactions in organic synthesis, providing important precursors and substrates in various coupling reactions. Hazardous and toxic elemental bromine is utilized in a conventional bromination reaction. To avoid the use of bromine, considerable efforts have been devoted to develop an environmentally-favorable bromination method with a bromide ion as a bromide source. Vanadium bromoperoxidase catalyzes two-electron oxidation of a bromide ion in the presence of hydrogen peroxide, affording a bromonium cation-like species, which induces the bromination of organic compounds. So, the bromination reaction mimicking a catalytic activity of vanadium bromoperoxidase has attracted much attention. These methodologies, however, require a stoichiometric amount of a strong oxidant to generate a bromonium-like species. A more practical catalytic bromination reaction system without use of hazardous reagents is to be developed. From the view point of green chemistry perspective, molecular oxygen is considered as an ideal oxidant. We embarked upon the development of an environmentally-favorable catalytic system for selective bromination of a wide range of substrates. In this presentation, versatile and practical catalytic bromination systems by the combination of a commercially available inexpensive vanadium catalyst and a Brønsted acid or a Lewis acid under molecular oxygen will be described.
