Synthesis of Novel Heterocyclic Structures via Reaction of Isocyanides with S-trans-Enones

Abstract

The reaction of enone 1, bearing an internal nucleophilic moiety, i.e., furan or pyrrole (X = O, NR'), with isocyanides is presented. The formation of products resulting from the reaction of the zwitterionic intermediate 2 with a second equivalent of isocyanide prior to cyclization to give 3, as well as the direct formation of 4 from 2, is described.

Organic transformations of isocyanides classified by their activation strategies

“…Early examples were reported using gallium(III) chloride (GaCl 3 ) as a moderate Lewis acid, which was sufficient to activate the heteroatoms of the electrophiles but prevented overinsertion 27 . In some cases, stronger Lewis acids, such as Et 2 AlCl 28 or AlCl 3 , 29 were used, together with the subsequent cyclization process, to prevent overinsertion. Recent advances in this approach revealed a new class of Lewis acids that selectively activate the electrophilic components in the presence of isocyanide, such as Ag, 30 Yb, 31 and In 32 (Scheme 7a).…”

Recent Advances of Indium(III) Chloride Catalyzed Reactions in Organic Synthesis

“…Isocyanide insertion reactions catalyzed by various matal [87] in organic synthesis have a great valuable addition to the organic chemist since it serves as a CÀ C and C-heteroatom bond forming reactions. [88] Very common single isocyanide insertion reactions [87a] and double isocyanide insertion reactions [89] which are comparatively less common catalyzed by Lewis acids are reported by different authors. Triple isocyanide insertion reaction has been described by Zhu and co-workers in 2013, where carboxylic acids and isocyanides produced polysubstituted oxazoles.…”

Exploring the Reactivity of Propargylic Ester: Acyloxy and Acyl Migratory Rearrangement Relay Enabled by Formal Double Isocyanide Insertion

“…[14][15][16] Compared with the popularity of single isocyanide insertion, successful examples on double and multiple isocyanide insertion are still limited. [17] In the past years, we have made great efforts to develop novel reactions involving isocyanides. [18] In this regard, our group has disclosed an efficient reaction of propargylic acetate with isocyanide to afford polysubstituted furan derivatives.…”