Ir‐Catalyzed Intramolecular Cyclization of 2‐Alkynyl Diaryl Sulfides for the Selective Synthesis of Sulfur‐Containing Polycyclic Compounds

Abstract

We describe an Ir-catalyzed intramolecular reaction of 2-alkynyl diaryl sulfides, which gives 9-arylidene-9H-thioxanthene derivatives via 6-exodig cyclization. When 2-alkynylphenyl naphthyl sulfides are used, divergent synthesis of triarylfused thiepines and diaryl-substituted benzothiophenes can be achieved by simply choosing the reaction temperature.

Sulfide‐Directed Ir‐Catalyzed Vinylic sp2 and Benzylic sp3 C−H Activation for the Construction of Sulfur‐Containing Medium‐Ring System

“…[14] Cycloadduct 2 a was oxidized to the sulfone, and its structure was determined by X‐ray analysis (Figure 1). The formation of the Z ‐isomer indicates that the present transformation was initiated by vinylic sp 2 C−H activation, not the π‐activation of the alkyne moiety [13] . The Rh counterpart did not give 2 a at all (entry 2).…”

“…The formation of the Z-isomer indicates that the present transformation was initiated by vinylic sp 2 CÀ H activation, not the π-activation of the alkyne moiety. [13] The Rh counterpart did not give 2 a at all (entry 2). The choice of counterion of the Ir catalyst was critical: BF 4 was inactive and alkyne 1 a was recovered in 86 % yield even after 2 h (entry 3).…”

“…Surprisingly, dibenzothiepine 5a via sp 3 CÀ H bond cleavage was the major product, and the conventional thioxanthene 6a via sp 2 CÀ H bond cleavage was the minor product. [13] Cycloadduct 5a was oxidized to a sulfoxide, and its structure was determined to be a dibenzo[b,f]thiepine derivative by X-ray analysis (Figure 2). The high reaction temperature promoted the double bond isomerization.…”

“…We next conducted an intramolecular reaction of o ‐tolyl sulfide 4 a at a high temperature for 24 h (Table 3). Surprisingly, dibenzothiepine 5 a via sp 3 C−H bond cleavage was the major product, and the conventional thioxanthene 6 a via sp 2 C−H bond cleavage was the minor product [13] . Cycloadduct 5 a was oxidized to a sulfoxide, and its structure was determined to be a dibenzo[ b , f ]thiepine derivative by X‐ray analysis (Figure 2).…”

Fe3O4@ABA-aniline-CuI nanocomposite as a highly efficient and reusable nanocatalyst for the synthesis of benzothiazole-sulfide aryls and heteroaryls

“…Studying diaryl suldes is important in organic synthesis because a large number of natural and medicinal products contain sulde scaffolds. [48][49][50] Diaryl suldes are one of the most important sulfur-containing organic compounds in the chemical, biochemical, biological and industrial industries. [51][52][53] Therefore, extensive studies have been conducted in order to provide new methods for the synthesis of these compounds.…”