Rhodium(III)‐Catalyzed Activation of CH Bonds and Subsequent Intermolecular Amidation at Room Temperature

Abstract

Disclosed herein is a Rh(III)-catalyzed chelation-assisted activation of unreactive C(sp3)-H bonds, thus enabling an intermolecular amidation to provide a practical and step-economic route to 2-(pyridin-2-yl)ethanamine derivatives. Substrates with other N-donor groups are also compatible with the amidation. This protocol proceeds at room temperature, has a relatively broad functional-group tolerance and high selectivity, and demonstrates the potential of rhodium(III) in the promotive functionalization of unreactive C(sp3)-H bonds. A rhodacycle having a SbF6(-) counterion was identified as a plausible intermediate.

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

“…[86] Oxime 182 is arylated with diaryliodonium salt 47 to afford 183. Ther esearch groups of You [87] and Glorius [88] accomplished the pyridine-directed CÀHf unctionalization with Rh III precatalysts (Scheme 31). Youand co-workers achieved the amination of pyridine 12 by using nitrobenzenesulfonamide (NsNH 2 )a st he nitrogen source and PhI(OAc) 2 as an oxidant.…”

Komplementäre Strategien für die dirigierte C(sp3)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer

“…Ohne das HydrosilanIntermediat zu isolieren, wird die Silylierung der C-H-Bin- -Katalysator 176 eingesetzt werden kann, um sekundäre C-H-Bindungen zu silylieren [82] oder borylieren, [83] wie durch die Borylierung der Cyclohexyl-C-H-Bindung des Hydrosilans 175 unter Bildung des Boronats 177 demonstriert wurde.Die resultierende C-B-Bindung kann durch nachfolgende Reaktionen in eine C-O-, C-N-oder C-C-Bindung überführt werden. You [87] und Glorius [88] …”

Intramolecular Amido Transfer Leading to Structurally Diverse Nitrogen‐Containing Macrocycles

“…[1] Fort his reason, efficient and selective catalytic CÀHa mination has been of much interest to researchers. Although intermolecular C À Ha mination for both C(sp 2 ) À H and C(sp 3 ) À Hb onds based on this inner-sphere pathway has been well documented, [8] the intramolecular approach is much less explored. [4] In the former approach, aC À Nb ond is constructed mainly by the insertion, of the initially generated metal-imido intermediates into CÀHb onds of hydrocarbon substrates.…”

“…[2,3] In general, two distinct mechanistic scaffolds can be conceived for functionalization of C À Hb onds:o uter-a nd inner-sphere pathways (Scheme 1a). Although intermolecular C À Ha mination for both C(sp 2 ) À H and C(sp 3 ) À Hb onds based on this inner-sphere pathway has been well documented, [8] the intramolecular approach is much less explored. [5] In the case of C(sp 2 )ÀHf unctionalization, while the intermolecular version of CÀNb ond formation is rarely explored, [6] thei ntramolecular reaction has been widely explored, via putative metal-nitrenoid intermediates,t hus leading to medium-sized (5-to 7-membered) azacycles (Scheme 1a,b ottom left).…”