Zn(OAc)₂-catalyzed tandem cyclization of isocyanides, α-diazoketones, and anhydrides: a general route to polysubstituted maleimides

Abstract

A zinc-catalyzed three-component reaction of isocyanides, α-diazoketones, and anhydrides has been realized as a novel and efficient method for the synthesis of polysubstituted maleimides.

Synthesis of Polysubstituted Maleimides via Metal-Free Cascade Reaction of Isocyanides and α-Diazoketones

“…This reaction does not require metal catalysts and additives, and features easily available substrates, green reaction conditions, high atom economy, and cascade conversion in a one-pot manner. Moreover, it provides a greener and more convenient way to construct polysubstituted maleimides …”

Transition Metal and Inner Transition Metal Catalyzed Amide Derivatives Formation through Isocyanide Chemistry

“…A method for synthesis of cyclic maleimides 145 based on the three-component cycloaddition reaction of isocyanides, -diazo ketones 144, and anhydrides was developed by Zhao and co-workers (Scheme 45). 106 Mechanistically, diazo ketone 144, under thermal conditions undergo a Wolf rearrangement to generate ketene intermediate 146, which is activated with Zn(II) towards nucleophilic addition of isocyanide. There are two possibilities for the formation of in-termediate 148 which can be obtained from the reaction of 147 and anhydride (path 1) or from the nucleophilic attack of the carboxylate ion and Passerini-type rearrangement (path 2).…”

NaN(SiMe3)2/CsTFA Copromoted Aminobenzylation/Cyclization of 2-Isocyanobenzaldehydes with Toluene Derivatives or Benzyl Compounds: One-Pot Access to Dihydroquinazolines and Quinazolines

“…In 2019, a similar NaN­(SiMe 3 ) 2 -mediated aminobenzylation of aldehydes with azaarylmethylamines was carried out by the same research group, with the generation of vicinal diamines (Scheme b) . As a continuation of our studies on the applications of isocyanides, herein we report a NaN­(SiMe 3 ) 2 /CsTFA copromoted aminobenzylation/cyclization reaction of 2-isocyano­benzaldehydes with toluene derivatives or benzyl compounds (Scheme c). The reaction works with a broad range of toluene derivatives and benzyl compounds, and provides a simple and efficient method for the synthesis of 4-benzyl-substitued dihydroquinazoline and quinazoline derivatives from easily available acyclic starting materials in a single step (Scheme c).…”