Iridium-Catalyzed Migratory Terminal C(sp³)–H Amidation of Heteroatom-Substituted Internal Alkenes via Olefin Chain Walking

Abstract

Hydroamination facilitated by metal hydride catalysis is an appealing synthetic approach to access valuable nitrogen-containing compounds from readily available unsaturated hydrocarbons. While high regioselectivity can be achieved usually for substrates bearing polar chelation groups, the reaction involving simple alkenes frequently provides nonselective outcomes. Herein, we report an iridium-catalyzed highly regioselective terminal C­(sp3)–H amidation of internal alkenes utilizing dioxazolones as an amino source via olefin chain walking. Most notably, this mechanistic motif of double bond migration to the terminal position operates not only with dialkyl-substituted simple alkenes including styrenes but also with heteroatom-substituted olefins such as enol ethers, vinyl silanes, and vinyl borons, thus representing the first example of the terminal methyl amidation of the latter type of alkenes through a nondissociative chain walking process.

Organo‐Photocatalytic Anti‐Markovnikov Hydroamidation of Alkenes with Sulfonyl Azides: A Combined Experimental and Computational Study

“…With the optimal conditions in hand, the substrate scope of alkenes was next explored, including both activated and unactivated alkenes (Table 2). First, a wide range of styrene derivatives, bearing an electron-donating or electron-withdrawing group (such as alkyl, alkoxy, phenyl, halogen or Bpin group) at the para-position of phenyl group, could undergo this anti-Markovnikov hydroamidation reaction with 2, affording the corresponding hydroamidation products in moderate to excellent yields (3)(4)(5)(6)(7)(8)(9)(10)(11). In addition, for ortho-and meta-substituted styrenes, the desired products (12)(13)(14)(15)(16)(17)(18)(19) are achieved in moderate to good yields (44-78 %).…”

“…Moreover, Zhang and co‐workers developed an elegant metalloradical catalysis (MRC) strategy, [5] from which organic azides could be converted to α‐metalloaminyl radicals and further involving C−H aminations and aziridinations. In particular, for transition‐metal‐catalyzed alkene hydroamidation reaction with dioxazolones, both Markovnikov and anti‐Markovnikov hydroamidation protocols have been established with a variety of transition metal catalysts [6–12] …”

“…In particular, for transition-metalcatalyzed alkene hydroamidation reaction with dioxazolones, both Markovnikov and anti-Markovnikov hydroamidation protocols have been established with a variety of transition metal catalysts. [6][7][8][9][10][11][12] Meanwhile, photocatalysis provides more opportunities for practical transformations of nitrene precursors, especially for organic azides. [13][14][15] Generally, two strategies have been applied to promote the conversion of organic azides to reactive species under photochemical conditions.…”

Amide-Directed Rhodium-Catalyzed Chain-Walking Hydrothiolation of Internal Alkenes

“…Recent advancements in chain-walking hydrofunctionalization have introduced diverse carbon-based functional groups at specific positions on the alkyl chains. However, this method faces several challenges: (1) The limited number of chain-walking processes that introduce heteroatoms, − especially sulfur atoms, , are reported compared to those forming C–C bonds. − (2) A hydride source is required to facilitate the reaction, especially in prevalent nickel-catalyzed reactions. − ,,,,, (3) Using sterically demanding trisubstituted alkenes poses challenges, especially in the chain-walking hydrothiolation process. , There are two examples of chain-walking hydrothiolation; one involves nickel-catalyzed hydrothiolation of alkenes using pinacolborane as a hydride source, and the other involves palladium-catalyzed hydrothiolation of terminal alkenes with an acid co-catalyst (Scheme A) . Although these reactions represent rare examples of chain-walking hydrothiolations, they address only a few of the aforementioned challenges.…”

Rhodium(III)-Catalyzed Remote Hydroamidation of Internal Alkenes Via Chain Walking

“…With this as the starting point, we envisioned that undirected remote hydroamidation of internal alkenes should be feasible (Scheme D). During the course of review of this work, Chang disclosed a conceptually related transformation …”