Heterogen katalysierte direkte C‐H‐Thiolierung von Heteroarenen

Abstract

Die erste generelle Methode zur direkten Thiolierung elektronenreicher Heteroarene wird vorgestellt. Sie nutzt den kommerziell erhältlichen Heterogenkatalysator Pd/Al 2 O 3 und CuCl 2 .

Sulfonium Salts Enable the Direct Sulfenylation of Activated C(sp3)−H Bonds

“…Then, the amount of DMSO was increased to 3.0 equiv, and the desired sulfenylation product 4 a was gained in 50 % yield after 10 h (Table 1, entry 2). Subsequently, various electrophilic activators were screened, and a similar yield of 4 a was achieved with acetyl chloride as an activator (Table 1, entry [3][4][5][6][7][8]. With the suitable activator in hand, we continued to amplify the amount of DMSO from 4.0 to 10.0 equiv.…”

“…Lactonederived β-ketoesters also underwent the α-sulfenylation reaction well, and converted into the corresponding products with good yield (4 d). Similarly, acyclic β-ketoesters bearing electrondonating groups (À Me, À Bn) and electron-withdrawing groups (À Cl, À F) at α-position could conduct the direct CÀ H bond methylthiolation and produce the expected products in moderate to good yield (4 e, 4 f, 4 g, 4 h), of which electron-withdrawing groups (À Cl, À F) and more sterically congested group [f] CH 3 CN 8.0 AcCl 20 min 50 20 [g] CH 3 CN 8.0 AcCl 3.5 h 68 21 [h] CH 3 CN 8.0 AcCl 2.0 h 74 22 [i] CH 3 CN 8.0 AcCl 25 min 76 23 [j] CH 3 CN 8.0 AcCl 25 min 77 24 [k] CH 3 (À Bn) at α-potision resulted in lower yields and longer reaction time. The reactivity of β-ketoesters derived from heteroaromatic furan and thiophene was also investigated, and the desired products were observed in moderate yields (4 i, 4 j).…”

“…Among these methodologies, direct sulfenylation of CÀ H bond to form CÀ S bond is a concise and atom-economic approach which has attracted great attention from organic chemists. A variety of sulfenylation agents such as thiols, [2] disulfides, [3] arenesulfonyl/ phenylsulfenyl chloride, [4] sulfonyl hydrazides, [5] sulfinic acids, [6] sodium sulfinates, [7] N-thioimides, [8] and triazole derivatives [9] have been employed in the formation of CÀ S bonds. Among them, α-sulfenylation of carbonyl compounds is especially attractive since these sulfenylated products are versatile building blocks and synthons in organic transformations.…”

Cobalt‐Catalyzed C−H Thiolation through Dehydrogenative Cross‐Coupling

“…[14] The direct thiolation of CÀHbonds presents an attractive strategy for the introduction of this valuable motif.N evertheless, despite recent advances in this direction [15] there is still need for complementary methods in order to attain ab roader utility of this transformation. [14] The direct thiolation of CÀHbonds presents an attractive strategy for the introduction of this valuable motif.N evertheless, despite recent advances in this direction [15] there is still need for complementary methods in order to attain ab roader utility of this transformation.…”

“…Thethioether moiety is common in bioactive compounds and intermediates in the synthesis of organic materials. [14] The direct thiolation of CÀHbonds presents an attractive strategy for the introduction of this valuable motif.N evertheless, despite recent advances in this direction [15] there is still need for complementary methods in order to attain ab roader utility of this transformation. Herein we report the unique reactivity of the Cp*Co III catalyst to promote the first cobaltcatalyzed CÀHthiolation.…”