Reusable directing groups [8-aminoquinoline, picolinamide, sulfoximine] in C(sp3)–H bond activation: present and future

Synthesis of Elaborate Benzofuran-2-Carboxamide Derivatives through a Combination of 8-Aminoquinoline Directed C–H Arylation and Transamidation Chemistry

“…Here, we could find that no C-H arylation took place in the absence of a directing quinoline moiety, which confirms that the 8-AQ auxiliary is indeed needed for enabling these reactions. Regarding the mechanism of the C-H arylation of these benzofuran derivatives, it is proposed to proceed via a Pd(II)/Pd(IV) cycle similar to those of other previously reported 8-AQ-directed C-H functionalization reactions (Scheme 4) [60][61][62]84]. The catalytic cycle begins with coordination of Pd(OAc) 2 to the substrate, which leads to the formation of intermediate A and the liberation of HX (where X = OAc or I).…”

Cobalt‐Catalyzed ortho‐Methylation of Ferrocenes Bearing ortho‐Directing Groups by Catalytic Directed C–H Bond Activation

“…[64,65] The catalytic ortho-methylation of 11 under standard reaction con-ditions gave rac-12 in 34 % yield (Scheme 3). [66,67] 8-Aminoquinolinecarboxamide 13 [68] was recently applied in a Pd-catalyzed ortho-alkylation by C-H activation, showing a preference for undergoing a second C-H activation with formation of dialkylated products when using 4 equiv. Addition of (-)-spartein did not improve the yield of the reaction.…”

Synthesis of a Bicyclic Azetidine with In Vivo Antimalarial Activity Enabled by Stereospecific, Directed C(sp3)–H Arylation

“…This approach would rely on cis -substituted azetidine 4 as a precursor, which we envisioned arising from a directed C–H arylation using commercially available d -azetidine-2-carboxylic acid 3 . Since the first examples exploiting 8-aminoquinoline as a directing group by Daugulis and co-workers, 10 C(sp 3 )–H functionalization methods have grown 11 and been applied to a number of challenging scaffolds, including cyclopropanes, 12 , 13 cyclobutanes, 13 , 14 cyclopentanes, 10b , 15 pyrrolidines, 16 and piperidines. 17 There are few reports of the use of azetidines as a substrate 18 or product 19 in C–H functionalization, and to our knowledge the C3 arylation of azetidines has not been described.…”