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Here we describe an asymmetric [3,3]-sigmatropic rearrangement of aryl iodanes that enables the enantioselective α-arylation of chiral 2-oxazolines, thereby producing valuable chiral α-aryl carbonyl compounds. The success of this protocol hinges on the selective assembly of aryl iodanes with 2-oxazolines and the smooth deprotonation of the in situ-generated iodonium-imine species. The nearly neutral and mild conditions of the reaction allow it to tolerate a wide variety of functional groups. Moreover, the remaining iodine atom in the products not only provides a versatile platform for further elaboration of such molecules but also supplies the asymmetric hypervalent iodine chemistry with a new class of chiral scaffolds.

Herein we describe the dearomatization of aryl sulfoxides with difluoroenol silyl ether (DFESE) using a rearrangement/addition protocol. The selection of the sulfoxide activator determines whether one or two difluoroalkyl groups are incorporated into dearomatized products. Using TFAA can deliberately halt the reaction at the mono-difluoroalkylated dearomatized intermediate formed via a [3,3]-rearrangement, which can be further trapped by external nucleophiles to give mono-difluoroalkylated alicycles. In contrast, switching to Tf 2 O enhances the electrophilicity of dearomatized intermediates, thus allowing for the adoption of a second DFESE to produce dual-difluoroalkylated alicycles., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Herein we describe the dearomatization of aryl iodanes through an unprecedented "rearrangement/addition" sequence. The process consists of two stages. First, a rapid [3,3] sigmatropic rearrangement of the aryl iodane with an α-stannyl nitrile affords a highly electrophilic dearomatized intermediate at -78 °C. A low-temperature rearrangement then enables the unstable dearomatized species to be trapped in situ with various nucleophiles. As a consequence, the reaction not only breaks the aromaticity of the aryl iodane but also sequentially installs two different functional groups, thus resulting in a polysubstituted alicyclic product., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A three-component reaction between benzyne, oxazolines and chloroform was developed for the synthesis of trichloromethylated chiral oxazolidines. Benzyne not only serves as an electrophile towards oxazolines but also acts as a base for the deprotonation of chloroform. The dual functions of benzyne enable the trichloromethylation of chiral oxazolines and thus construct chiral N,O-quaternary stereocenters.