Directing group strategies in rhodium-catalyzed C–H amination

Abstract

Construction of a carbon-nitrogen bond is one of the most prevalent operations in nature and organic synthesis. The resulting amino compounds are privileged structural fragments in natural products, pharmaceutical drugs,...

Additive-Free Copper-Catalyzed Benzylic C(sp3)–H Carbamation: Simple Preparation of Primary Benzylic Amines

“…For instance, several research groups have developed methods for the synthesis of alkyl tosylamides (R-NHTs) from the corresponding alkanes by the transfer of an N=SO 2 C 6 H 4 Me moiety through the use of such transition metals as Cu, Rh, or Ag. [16][17][18][19] The deprotection of the tosyl group requires harsh conditions [lithium naphthalenide, Na/K alloy on silica, Ni(0)acac/i-PrMgCl, Bu…”

Ir(iii)/Ag(i)-catalyzed directly C–H amidation of arenes with OH-free hydroxyamides as amidating agents

“…10 Particularly, significant progress has been made in C–H bond amidation reactions in recent years. 11 Heterocyclic compounds represented by pyrazole are excellent directing groups in C–H bond activation reactions, which catalyzed by Cp*Rh( iii ), Cp*Ir( iii ), Ru( ii ) and other metal. 12 At the same time, a series of amidation reagents, such as N -substituted hydroxylamines, 13 N -methoxyamide, 14 dioxazolones, 15 organic azide, 16 chloramines and other substrates, 17 have been widely used as C–N coupling partners for construction of structurally complex scaffolds.…”

Oxidative Nickel-Catalyzed ortho-C–H Amination of (Iso)quinolines with Alicyclic Amines Directed by a Sacrificial N-Oxide Group

“…Therefore, construction of the C­(pyridyl)–N­(alicyclic) bond is of fundamental importance in synthetic and medicinal chemistry . In the C–N bond forming toolbox, direct heteroaryl C–H/N–H coupling should be an ideal adoption as it eliminates extra costly steps to prefunctionalize either coupling partner. , However, unlike the exceptionally broad arene (especially those with Py ring-contained DGs) ,− and five-membered heterocyclic substrates (Scheme a and b), C–H bond aminations of a free or fused Py ring with free amines (especially aliphatic amines) still remain underdeveloped because primary/secondary amines and Py rings have the tendency to adopt a nonproductive N-bound coordination mode with TMs, to result in a significant decrease of catalytic reactivity (Scheme c) . To this end, it is highly desirable to explore ideal C–H amination on a free or fused Py ring, wherein developing more reactive TM catalysis or installing easily removable DGs with weaker coordination capability on pyridyl-nitrogen atoms is a potential solution.…”