PdCl₂-Promoted Electrophilic Annulation of 2-Alkynylphenol Derivatives with Disulfides or Diselenides in the Presence of Iodine

Abstract

An efficient synthesis of 3-chalcogen-benzo[b]furans via palladium-promoted annulation reactions of 2-alkynylphenol derivatives with disulfides or diselenides and iodide has been developed. In the presence of I(2) and PdCl(2), both 3-sulfenylbenzofurans and 3-selenenylbenzofurans were selectively prepared from the cyclization of 2-alkynyanisoles with disulfides or diselenides in moderate to excellent yields.

Iron‐Facilitated Iodine‐Mediated Electrophilic Annulation of N,N‐Dimethyl‐2‐alkynylanilines with Disulfides or Diselenides

“…We began our study by examining the reaction between N , N ‐dimethyl‐2‐(phenylethynyl)aniline ( 1a ) and 1,2‐diphenyldisulfane ( 2a ) to screen the optimal reaction conditions, and the results are summarized in Table 1. As expected, the reaction of N , N ‐dimethyl‐2‐(phenylethynyl)aniline ( 1a ) with 1,2‐diphenyldisulfane ( 2a ) was carried out smoothly under the reported reaction conditions (PdCl 2 combined with I 2 ),9 providing the desired product 3 in 84% yield (entry 1). It was interesting to find that an identical yield was achieved in the presence of I 2 alone (entry 2).…”

“…Recently, we were interested to find that chalcogenyl iodides could be derived in situ from the reaction of disulfides or diselenides with I 2 , which has been applied for the preparation of 3‐chalcogenobenzo[ b ]furans [Eq. (2)] 9. With a continuing interest in the synthesis of chalcogen‐containing heterocycles,9,10 we decided to investigate the feasibility of the preparation of 3‐chalcogen‐substituted indoles using the generation of chalcogenyl iodides in situ and an annulation strategy.…”

“…(2)] 9. With a continuing interest in the synthesis of chalcogen‐containing heterocycles,9,10 we decided to investigate the feasibility of the preparation of 3‐chalcogen‐substituted indoles using the generation of chalcogenyl iodides in situ and an annulation strategy. Here, we report a simple and efficient synthesis of 3‐chalcogenoindoles by electrophilic annulation of N,N ‐dimethyl‐2‐alkynylanilines with chalcogenyl iodides derived from disulfides or diselenides with I 2 [Eq.…”

Simultaneous Construction of C−Se And C−S Bonds via the Visible‐Light‐Mediated Multicomponent Cascade Reaction of Diselenides, Alkynes, and SO2

“…As ac lass of stable and availables ource of selenium, diselenides are preferred as selenylatinga gents. Selenium has been introduced into benzofuran, [2] indole, [3] naphthalene, [4] benzene, [5] andu nsaturated alkenes [6] by using diselenides as the source via the electrophilics eleniranium cation pathway.A seleniumm oiety can also be introduced via radical addition reaction. Sun and co-workers reported ar adical-initiated selenodifluoromethylation of alkenes promoted by coppers alt.…”

Metal-Free Synthesis of 3-Sulfenylindoles via an Iodine-Mediated Electrophilic Cyclisation of 2-Alkynylanilines with Disulfides

“…Here, we report the metal-free synthesis of 3-sulfenylindoles via an iodinemediated electrophilic cyclisation of 2-alkynylanilines with disulfides [Eqn (3), Scheme 1]. [15][16][17] * Correspondent. E-mail: taoliming2005@yahoo.com.cn…”