Overcoming the Limitations of C−H Activation with Strongly Coordinating N‐Heterocycles by Cobalt Catalysis

Abstract

Strongly coordinating nitrogen heterocycles, including pyrimidines, oxazolines, pyrazoles, and pyridines, were fully tolerated in cobalt-catalyzed C-H amidations by imidate assistance. Structurally complex quinazolines are thus accessible in a step-economic manner. Our findings also establish the relative powers of directing groups in cobalt(III)-catalyzed C-H functionalization for the first time.

Cobalt‐Catalyzed 2‐(1‐Methylhydrazinyl)pyridine‐Assisted Direct C−H/N−H Functionalization of Benzoyl Hydrazide with Isocyanide: Efficient Synthesis of Iminoisoindolinone Derivatives

“…[1] Furthermore, it would also provide new retrosynthetic approaches for the synthesis of complex natural products and late-stage derivatization of bioactive compounds. [2] In spite of the dramatic impact on synthetic chemistry, most of the CÀH functionalization protocols still involve the use of precious and rare transition metal catalysts, such as Rh, [3] Ir, [4] Pd, [5] and Ru, [6] which are not ideal due to the stringent environmental and economic requirements nowadays. Thus, our group along with others has focused on using earth-abundant cobalt catalysts for such CÀH bond activations by taking advantages of their unique merits, including high catalytic efficiency, inexpensive access, and low toxicity.…”

Cobalt‐Catalyzed Annulation Reactions via C−H Bond Activation

“…Later, Ackermann et al. published the synthesis of quinazoline moiety by the coupling of benzimidates 49 with dioxazolones 47 (Scheme ) . Other strongly coordinating directing groups such as pyrazole, pyridine, oxazole, and pyrimidine were installed in the benzimidate substrate and tested for its selectivity.…”

Direct Functionalization of C−H Bonds by Iron, Nickel, and Cobalt Catalysis

“…Other heterocyclic ring systems being synthesized using Cp*Co III catalysis include quinolines, [133a, 140] 1H-indazoles, [141] pyrroles, [142] quinazolines, [143] indolizines, [144] pyrido[2',1':2,3]pyrimido[1,6-a]indol-5-iums, [145] and2 H-chromenes. [146] In Scheme 35 it was already shown that the reactionw ith alkynes can lead to alkenylation in position-2 of indole.…”