Synthesis of Polysubstituted Iodoarenes Enabled by Iterative Iodine‐Directed para and ortho C−H Functionalization

The "I's" have it! Ar–I compounds can undergo two new types of aromatic C−H alkylation reactions from the readily accessible aryliodine λ³‐diacetate form. In this way, a benzyl group is coupled selectively at the para C−H position, while the sulfonylallylation takes place ortho to iodine.

Abstract

Among halogenated aromatics, iodoarenes are unique in their ability to produce the bench‐stable halogen(III) form. Earlier, such iodine(III) centers were shown to enable C−H functionalization ortho to iodine via halogen‐centered rearrangement. The broader implications of this phenomenon are explored by testing the extent of an unusual iodane‐directed para C−H benzylation, as well as by developing an efficient C−H coupling with sulfonyl‐substituted allylic silanes. Through the combination of the one‐shot nature of the coupling event and the iodine retention, multisubstituted arenes can be prepared by sequentially engaging up to three aromatic C−H sites. This type of iodine‐based iterative synthesis will serve as a tool for the formation of value‐added aromatic cores.

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