An Aminative Rearrangement of O‐(Arenesulfonyl)hydroxylamines: Facile Access to ortho‐Sulfonyl Anilines

Abstract

Ortho-sulfonyl anilines are important building blocks for a range of applications. We report the discovery of an aromatic rearrangement reaction of O-(arenesulfonyl)hydroxylamines which leads directly to ortho-sulfonyl anilines through formation of a new CÀ N bond with excellent levels of regiocontrol for the ortho position(s) over all others. We establish that the rearrangement is proceeding through an intermolecular mechanism and propose that the regiocontrol observed is the result of attractive non-covalent interactions occurring during the CÀ N bond-forming step. Importantly, this method is complementary to classical aniline sulfonation in terms of the variously substituted regioisomers that can be obtained and it is also applicable to O-(benzylsulfonyl) hydroxylamines.

Ortho-Selective amination of arene carboxylic acids via rearrangement of acyl O-hydroxylamines

“…In our previous work, we established that the related aminative rearrangement of sulfonyl O-hydroxylamines proceeded via an intermolecular mechanism, shown by extensive scrambling in crossover experiments. 18,23 In contrast, analogous experiments in the present system-i.e. subjecting carboxyl substrates 1b (delivering NH 2 ) and 3i (delivering NHMe) afforded no product crossover, which suggested that the reaction might proceed via an intramolecular mechanism (Scheme 3A).…”

“…This very particular requirement mirrors the prominence of TFA in related aminations that utilise N-O reagents though the reasons for this remain unclear. 15b, 18,25 To gain insight into the reasons for this strict acid dependence, we next investigated the role of hydroxylamine protonation on reactivity. Anticipating that deprotection of the Boc group might complicate investigation of the role of acid in the subsequent mechanistic steps, we commenced the investigation using benzoyl O-hydroxylammonium triate (9a) (Scheme 4).…”

Strategies That Utilize Ion Pairing Interactions to Exert Selectivity Control in the Functionalization of C–H Bonds

“…Our group has most recently demonstrated that this concept can enable an ortho-selective aminative rearrangement of O-(arenesulfonyl)hydroxylamines. 35 This was discovered during optimization of the earlier process and allows the facile synthesis of a diverse range of ortho-sulfonyl anilines (Figure 9a, n = 0). The addition of a methylene unit between the arene and sulfonate group was also well tolerated to give ortho-amino benzyl sulfonate products (Figure 9a, n = 1).…”

“…Our group has most recently demonstrated that this concept can enable an ortho -selective aminative rearrangement of O -(arenesulfonyl)­hydroxylamines . This was discovered during optimization of the earlier process and allows the facile synthesis of a diverse range of ortho -sulfonyl anilines (Figure a, n = 0).…”

Mn(OAc)3-Promoted Sulfonation-Cyclization Cascade via the SO3– Radical: The Synthesis of Heterocyclic Sulfonates

“…Therefore, sulfonation, as one of the most important organic reactions, is a well-accepted synthetic method to introduce the sulfonyl moiety (−SO 2 −) into molecules . Despite extensive studies of sulfonation methods spanning more than a century, the use of corrosive S (VI) sulfonating reagents, poor regio-selectivity, harsh reaction conditions (direct sulfonation), and the use of prefunctionalized halogenated substrates (indirect sulfonation) have become the bottlenecks that hamper the further development of sulfonyl chemistry, especially the synthesis of heterocyclic sulfonyl compounds.…”