Cobalt‐Catalyzed Coupling of Benzoic Acid C−H Bonds with Alkynes, Styrenes, and 1,3‐Dienes

Abstract

A method for cobalt-catalyzed, carboxylate-directed functionalization of arene C-H bonds is reported. Alkynes, styrenes, and 1,3-dienes can be coupled with benzoic acids to provide cyclic products in good yields. The reactions proceed in the presence of a cobalt(II) hexafluoroacetylacetonate catalyst, (TMS) NH base, Ce(SO ) cooxidant, and oxygen oxidant.

Electrochemical C−H Amination by Cobalt Catalysis in a Renewable Solvent

“…[1] Currently applied strategies for aniline syntheses heavily exploit metal-catalyzed cross-coupling reactions of organic electrophiles. [5] In sharp contrast, within our program on electrochemical CÀHactivation, [6] we have uncovered the first oxidative organometallic CÀH amination [7] that utilizes cheap and sustainable electricity [8] as the terminal oxidant, thus leading to H 2 as the sole byproduct. Am ore step-economical approach towards aromatic amines makes use of the direct amination of otherwise unreactive CÀHb onds, [3] thus avoiding the use of prefunctionalized aryl halides.…”

“…Am ore step-economical approach towards aromatic amines makes use of the direct amination of otherwise unreactive CÀHb onds, [3] thus avoiding the use of prefunctionalized aryl halides. [5] In sharp contrast, within our program on electrochemical CÀHactivation, [6] we have uncovered the first oxidative organometallic CÀH amination [7] that utilizes cheap and sustainable electricity [8] as the terminal oxidant, thus leading to H 2 as the sole byproduct. [5] In sharp contrast, within our program on electrochemical CÀHactivation, [6] we have uncovered the first oxidative organometallic CÀH amination [7] that utilizes cheap and sustainable electricity [8] as the terminal oxidant, thus leading to H 2 as the sole byproduct.…”

Carboxy Group as a Remote and Selective Chelating Group for C−H Activation of Arenes

“…The past decades have witnessed extensive studies in transition‐metal‐catalyzed C−H activation, whose site selectivity is largely dominated by a chelating functional group . The carboxy group, one of the most celebrated chelating groups, has proven to be highly effective for assisting proximity‐driven ortho ‐C(sp 2 )−H bond metalation of benzoic acids with metals such as Pd, Ru, Rh, and Ir through κ 1 coordination, and was pioneered by the groups of Miura and Satoh, Yu, Daugulis, Ackermann, Larrosa, as well as Gooßen and others (Scheme a) . The importance of κ 1 coordination of the carboxy group in promoting ortho ‐C−H activation of benzoic acids has been accounted for by Yu and co‐workers, who also devised a successful means of shifting the equilibrium from the preferred κ 2 to κ 1 coordination to the Pd center by utilizing a suitable countercation such as either Na + or NR 4 + .…”

Rhodium‐Catalyzed Annelation of Benzoic Acids with α,β‐Unsaturated Ketones with Cleavage of C−H, CO−OH, and C−C Bonds

“…[1] Initially, this approach was often limited by the use of complex directing groups, [2] which needed to be installed and later removed, thus adding steps to the overall process.Instate-ofthe-art methods,t he selectivity can be enforced even by ubiquitous functionalities,i ncluding ketone, [3] hydroxy, [4] or carboxylate groups. [6] Inspired by pioneering work by Miura and co-workers, [7] ah uge variety of carboxylatedirected sp 2 CÀH ortho-functionalizations have been developed for example,b yt he groups of Yu, [8] Li, [9] Daugulis, [10] Larrosa, [11] Ackermann, [12] Su, [13] Baidya, [14] our group, [15] and others. [6] Inspired by pioneering work by Miura and co-workers, [7] ah uge variety of carboxylatedirected sp 2 CÀH ortho-functionalizations have been developed for example,b yt he groups of Yu, [8] Li, [9] Daugulis, [10] Larrosa, [11] Ackermann, [12] Su, [13] Baidya, [14] our group, [15] and others.…”