Iridium‐Catalyzed ortho‐C−H Amidation of Benzenesulfonamides with Sulfonyl Azides

Abstract

We developed herein an iridium-catalyzed direct CÀ H activation/ CÀ N bond formation reaction of benzenesulfonamides with sulfonyl azides. The amidation reaction provides a protocol for the synthesis of 2-aminobenzesulfonamides in good to excellent yields. This strategy features a wide substrate scope, tolerates a broad range of functional groups under external oxidant-free conditions and only releases molecular nitrogen as the sole by-product. Moreover, the preliminary mechanism was investigated and the proposed reaction pathway was provided. Figure 1. Selected biologically active benzothidiazine-1,1-dioxides containing the 2-aminobenzenesulfonamides motif.

Iridium-promoted deoxyglycoside synthesis: stereoselectivity and mechanistic insight

“…3 ). 18 The dimer complex then dissociates into two transient monomeric Ir(COD)OTf complexes (see the ESI † ), which in turn coordinate to the glycal. We rationalize that for the 3,4,6-tri- O -benzyl glycal donor 1a , the iridium metal center coordinates to the olefinic C1 and C2 carbon to form stable η 2 π-allyl intermediates, while for the 3- O -acetyl-4,6-di- O -benzyl- d -galactal donor 1u , which carries a better leaving group at the 3-position, the Ir(COD)OTf species first coordinates to C1 and C2 to form η 2 π-allyl intermediates, and then, upon dissociation of the triflate anion from the metal center, the metal center further coordinates with C3 to form an η 3 π-allyl complex, expelling the 3-acetyl substituent as an acetate anion, which may then coordinate to the metal center as a free ligand ( Fig.…”

Decoding Directing Groups and Their Pivotal Role in C−H Activation

“…[247] However, some examples of S-based directing groups such as thioethers, [134,[248][249][250][251] sulfoxides [252][253][254][255] , and thioamides [256][257][258][259] have evolved as an efficient strategy to achieve new CÀ H functionalization. Another strategic use for S-based groups is to use sulfur-tethered groups as removable and/or easily modifiable directing groups such as sulfonamides, [260][261][262][263][264] sulfoximines [265][266][267][268][269] and sulfonyl bridged groups. [89,106,[110][111][112][113][114][115] In this section, we present some important examples of these substrates and most importantly the synthetic pathway to achieve such compounds.…”

The Role of Sulphonamides and N‐Sulphonyl Ketimines/Aldimines as Directing Groups in the Field of C−H Activation

“…Sheng and co‐workers [49] developed iridium‐catalyzed C−N bond formation on N ‐acetyl benzene sulphonamide ( 28 ) through C−H activation. The traditional method of producing aminobenzene sulphonamides require harsh reaction conditions, narrow substrate scope and isomer formation.…”