Oxidative ipso-Rearrangement Performed by a Hypervalent Iodine Reagent and Its Application
摘要:
An oxidative ipso-rearrangement mediated by a hypervalent iodine reagent that enables rapid generation of a functionalized dienone system containing a quaternary carbon center connected to several sp(2) centers has been developed. The process occurs through transfer of an aryl group from a silyl segment present on the lateral chain. As an illustration of the potential of this transformation, a total synthesis of sceletenone, a small alkaloid, is described.
Treatment of phenols or anilines containing a sulfonyl group in the presence of a hypervalent iodine reagent promotes a formal dearomatizing [2 + 3] cycloaddition reaction on unactivated benzene and naphthalene derivatives. This process occurs via an intramolecular nucleophilic addition to the Wheland species generated during the oxidative activation. Subsequent treatment under acidic conditions readily transforms the tricyclic system into a biaryl via a formal cross-coupling process.
Oxidation of N-aromatic methanesulfonamides with iodobenzene diacetate in the presence of substituted thiophene promotes interesting coupling reactions in moderate to good yields.