Heterogeneously Catalyzed Direct CH Thiolation of Heteroarenes

Abstract

The first general methodology for the direct thiolation of electron-rich heteroarenes was developed by employing Pd/Al2 O3 , a recoverable and commercially available heterogeneous catalyst, and CuCl2 . This method represents an operationally simple approach for the synthesis of these valuable compounds. Preliminary mechanistic studies indicate a heterogeneous catalytic system, in which both metals play a complementary role in the formation of the thiolated products.

Nickel‐Catalyzed C−H Chalcogenation of Anilines

“…[3] In this context, CÀHc halcogenations have gainedc onsiderable attention, predominantly relyingo nt he use of precious4 dt ransition metals. [4] In light of the economic benefits associated with 3d transition metal complexes,t he recent focus has, however, shifted towards the use of earth-abundant-metal catalysts, [3c, 5] with considerable advances being realized in nickel-catalyzed CÀHa ctivations. [5e, 6] Despite the undisputable progress in the nickel-catalyzed CÀHt hiolation, [7] the previously established methods were largely restricted to electron-deficient benzamide derivatives bearing bidentate [8] directing groups.…”

Copper‐Catalyzed Regioselective Sulfenylation of Indoles with Arylsulfonyl Chlorides

“…[3] Therefore, many procedures have recently been developed for the direct 3-arylthiolation of indoles.In 2004, Uemura and co-workers reported av anadium-catalyzed protocol for the sulfenylation of indoles with thiols. [4] Later,o ther metal catalysts such as iron, [5] copper [6] and palladium [7] salts were also efficientlye mployed for such transformations. Also, metal-free reactions have been intensively explored by using diverse sulfenylating agentss uch as disulfides, [8] sulfenyl halides, [9] sulfonyl hydrazides, [10] sodium sulfinates, [11] sulfinic acids, [12] thiols, [13] and so on, [14] in combinationw ith iodine, oxidants, N-bromosuccinimide (NBS), or some simple bases.…”

Direct oxidative C(sp3)─H/C(sp2)─H coupling reaction using recyclable Sr‐doped LaCoO3 perovskite catalyst

“…Uses of metal oxides in organic synthesis are extensively emerging. On introduction of active metals into the framework of oxide supports using impregnating methods, catalytic activity and thermal stability of transition metals are improved . Many methods that allow for the synthesis of heterocycles from metal oxide‐catalyzed, direct C─H functionalization are known .…”

“…On introduction of active metals into the framework of oxide supports using impregnating methods, catalytic activity and thermal stability of transition metals are improved. [36][37][38] Many methods that allow for the synthesis of heterocycles from metal oxidecatalyzed, direct C─H functionalization are known. [39,40] Mixtures of metal oxides are also calcined to feature synergistic effects, thus improving efficiency.…”