Carbon-carbon and carbon-hydrogen bond transformations mediated by highly reactive radicals and their application to the synthesis of bioactive compounds

Reactive free radicals have wide applications in organic synthesis due to their remarkable chemical properties that allow useful molecular transformations. The present review covers the author's recent studies on the utilization of radical species in chemical synthesis of organic molecules: The first topic deals with two types of alkoxyl radicals (primary or tertiary) that selectively undergo dehydrogenation or β-scission to give rise to the key structural elements of (-)-CP-263,114, a ras-farnesyl transferase inhibitor. The second part of this review describes the development of new carbon-carbon bond forming reactions that proceed via the direct and selective abstraction of the hydrogen from the sp³C-H bond adjacent to oxygen or nitrogen. In this radical C-H bond transformation, triethylborane serves not only as a source of hydrogen abstractor but as an alkoxyl radical scavenger that enables the irreversible addition of carbon radicals to carbon-oxygen double bonds.