External-Oxidant-Based Multicomponent Reactions

Abstract

This short review covers an innovative approach in multicomponent chemistry involving the employment of an external oxidant. This approach is exploited either to generate one of the reagents of the multicomponent reaction (MCR) or to transform one advanced intermediate into a final stable product. Both aspects are critically analyzed and examples taken from the recent literature are discussed in detail. 1 Introduction 2 Generation of One Reactant through an Oxidative Process 2.1 Passerini Reactions 2.2 Ugi-Type Reactions 2.3 Other Multicomponent Reactions 3 Oxidation of an Advanced Intermediate as a Driving Process 3.1 Aromatization of a Reaction Intermediate 3.2 Oxidation of an Advanced Intermediate without Aromatization 4 Conclusion

Study and application of graphene oxide in the synthesis of 2,3-disubstituted quinolinesviaa Povarov multicomponent reaction and subsequent oxidation

“…Nevertheless, GO-assisted one-pot multistep reactions have been seldom explored, 34 at least using organo-or metal-functionalized GO composites. 35 Building on our experience in the development of new synthetic methodologies using MCRs [36][37][38][39][40][41][42][43][44] and in one-pot multistep processes, 45,46 and inspired by the potential of MCRs involving the employment of an external oxidant, 47 we decided to study the GO-promoted Povarov multicomponent reaction between anilines, aldehydes and 2,3-dihydrofuran (DHF) that acts as dienophile to give tetrahydroquinolines (THQs) 1, and their subsequent oxidation to 2,3 disubstituted quinolines 2 (Scheme 1).…”

Gold-catalyzed multicomponent reactions

“…Over the years, transition metal-catalyzed MCRs have emerged as an important branch in organic synthesis. 3 In the domain of transition metal catalysis, gold complexes were considered to be inert and labelled “catalytically dead” species. 4 Hence, gold has remained in the shadow of other metals for a long time.…”

The 100 facets of the Passerini reaction

“…In 2010 we have obtained oxazolines 9, this time exploiting, as an additional functional group, an azide placed on the aldehydic component ( Scheme 4 ). 13 Since α-azidoaldehydes 8 are rather unstable, we used an in situ oxidation protocol 14 of α-azidoalcohols 7 with IBX. The Passerini adducts were then cyclized using supported triphenylphosphine in a Staudinger–aza-Wittig reaction.…”