Synthesis of N‐Alkyl and N‐H‐Carbazoles through S_NAr‐Based Aminations of Dibenzothiophene Dioxides

Abstract

Alkyl amines have become available for the synthesis of diverse N‐alkyl carbazoles through twofold SNAr aminations of dibenzothiophene dioxides by using alkali metal bases. Of particular importance is the choice of counter cations on alkali metal bases, that is, i) the use of Li base for the efficient intermolecular reaction and ii) the sequential addition of heavier alkali metal bases (Na, K, or Cs) to promote intramolecular cyclization in a one‐pot manner. This protocol also enables the cascade synthesis of N‐H‐carbazoles by using 2‐phenylethylamine by removal of the 2‐phenethyl group from N‐(2‐phenethyl) carbazoles in a single operation.

Transformation of Thia[7]helicene to Aza[7]helicenes and [7]Helicene-like Compounds via Aromatic Metamorphosis

“…Recently, it has been reported that dibenzothiophenes can be converted into a variety of ring systems, such as dibenzosiloles, dibenzophospholes, fluorenes, and carbazoles [ 22 , 23 , 24 , 25 , 26 ]. Transformation to dibenzosiloles and dibenzophospholes involves (1) the generation of 1,1′-dianions via desulfurative dilithiation with lithium metal and (2) the subsequent reaction of the resulting 1,1′-dianions with silicon and phosphorus electrophiles, respectively.…”

Divergent reactivity of sulfinates with pyridinium salts based on one-versustwo-electron pathways

“… 1 They can also serve as versatile building blocks for further modification or as reagents in many chemical transformations. 2 Accordingly, selective incorporation of sulfonyl moieties into organic commodities has received considerable attention in both chemistry and biology. 3 Conventional approaches include Friedel–Craft type sulfonylation of arenes, 4 oxidation of sulfides, 5 and nucleophilic aromatic substitution (S N Ar).…”

Construction of 5H‐Dibenzo[c,e]azepine Framework from Dibenzothiophene Dioxides andN‐Benzylimines through SNAr Reactions

“…Dibenzothiophene dioxides 1b, [22] 1c, [22] 1d, [22] and imine 5 [28] were prepared according to the literature procedures.…”