オルガノコバロキシムの反応と合成への応用

Abstract

Alkyl- and alkenylcobaloximes are conveniently prepared by the reaction of cobaloxime (I) with alkyl halides, vinyl halides, and acetylenes. The organocobaloximes thus obtained are convenient and versatile radical source for organic syntheses. The cobaloxime group is conveniently transformed into other functions by a variety of radicophiles. The organo radical from organocobaloxime attacks intramolecular or intermolecular olefin in the same manner as a general organo radical. Contrary to the conventional tin hydride method, an organocobaloxime gives not a reduction product but an olefinic product. The olefinic function thus formed is useful for further chemical transformation. The coexisting cobaloxime (II) radical modifies reactivity of the olefinic and arenic part of the organo radical containing sulfur function. The cobaloxime moiety activates an intramolecular diene and arene system to cause cycloaddition and aromatic substitution respectively.