Iminoiodanes and C-NBond Formation in Organic Synthesis

Abstract

Structurally related to iodosylbenzene PhI=O, iodonium imides PhI=NR, off-white to pale yellow solids of low solubility, belong to the class of hypervalent iodine(III) reagents and were first prepared nearly thirty years ago. Two additional decades were needed before they could be considered as useful nitrene precursors with the discovery of the copper-catalyzed aziridination of olefins. Since then, iminoiodanes have been successfully applied in the total synthesis of natural and/or biologically active compounds. Recent developments aimed at circumventing their tedious preparation led to the discovery of one-pot nitrogen transfers from sulfonamides, sulfamates, or carbamates mediated by iodosylbenzene(diacetate) PhI(OAc) 2 or iodosylbenzene. Reliable functionalizations of alkanes and alkenes via C-H insertion or aziridination using copper or rhodium catalysts can now be considered as synthetically useful processes.

Chemoselectivity and the Curious Reactivity Preferences of Functional Groups

“…[185] Müller et al studied intermolecular CÀH amination with stable tosyl-and nosyl-functionalized iminoiodinanes, but a large excesse of alkane was required to achieve acceptable yields. [186] The problems generally associated with the isolation and purification of nonstabilized iminoiodananes [187] was circumvented by Che and co-workers with the development of an in situ protocol that generated nitrenes from TsNH 2 and PhI(OAc) 2 in the presence of a manganese-porphyrin catalyst. [188] The practicality of C À H aminations employing metal nitrenes was dramatically increased by a report from Espino and Du Bois, who detailed a highly chemo-and stereoselective process whereby oxazolidinones 217 could be prepared from carbamates 216 through an intramolecular CÀH amination (Scheme 91).…”

Imination of Sulfides and Sulfoxides with Sulfonylimino‐λ3‐Bromane under Mild, Metal‐Free Conditions

“…[1] Recent developments in simple methodologies for the generation of imino-l 3 -iodanes in situ have greatly enhanced research activity in this area. [2] Sulfonylimino-l 3 -iodanes readily generate active metal-nitrenoid species under mild conditions [1] because of the hyper-leaving-group ability of aryl-l 3 -iodanyl groups.…”

Silver‐Catalyzed Intermolecular Amination of CH Groups

“…However, success has been mostly restricted to aziridination of olefins, sulfoxide imination, and intramolecular CÀH amidation. [2] CÀH amination chemistry has long been an active research area. In the past two decades, various catalysts utilizing iron, manganese, rhodium, ruthenium, and copper have been developed to mediate nitrene insertion reactions.…”