An Overview of Rhodium‐Catalysed Multi‐Component Reactions

Abstract

Multi‐component reactions have emerged as a powerful synthetic tactic for modern synthetic organic chemists for performing Diversity Oriented Synthesis. In recent years, with the advent of transition metal‐catalysed multi‐component reactions, rhodium catalysed reactions have proven to be promising candidates for delivering highly functionalized products. This review provides an overview of the rhodium‐catalysed multi‐component reactions leading to the formation of various types of compounds such as carbocycles, heterocycles of different types, spirocompounds, vicinal diols, amino acid derivatives etc.

Dirhodium(II)/Xantphos-Catalyzed Relay Carbene Insertion and Allylic Alkylation Process: Reaction Development and Mechanistic Insights

“…Although the exact mechanism of the reaction is still not clear, a tentative mechanism for this relay catalysis is proposed in Scheme based on the results herein and previous studies . Both the phosphine-free and Xantphos-coordinated [Rh­(II) 2 ] can catalyze carbene insertion reaction, affording the intermediate 4 (Cycle I).…”

“…However, no 6a was observed in the absence of any single component of Rh 2 (Oct) 4 , Xantphos or Cs 2 CO 3 (94% vs 0%, Scheme a). These results above suggested a relay carbene-induced N–H insertion and [Rh 2 ]/Xantphos-catalyzed allylic alkylation process, which is different from the well-known binuclear Rh­(II)-catalyzed MCRs, wherein a mechanism involving an oxonium ylide generated in situ and trapped by the third component directly . Notably, neither the allylic amination nor cyclopropanation reaction was favorable when 3a was treated with 1a or 2a under the standard conditions (Scheme b,c, respectively), which could be the key factors for the success of the titled three-component reaction.…”

“…Dirhodium­(II) complexes of the tetracarboxylate type have been widely utilized in the discovery and development of valuable synthetic methodologies. − Especially, dirhodium­(II) complexes-catalyzed multicomponent reactions (MCRs) involving electrophilic trapping of metal-associated onium ylide intermediates generated in situ from metal carbenoids with various nucleophiles have emerged as a powerful protocol for construction of structurally complex and diverse molecules (Scheme a) . Trapping of onium ylides by nucleophilic addition to aldimines, carbonyls, activated alkenes (Michael acceptors) and so on, as well as a few examples via the formal S N 1 pathway, have been reported. − Despite the recent progress and the great significance of allylic group in organic synthesis, the introduction of allylic moiety as the third component through allylic metal intermediate remains a formidable challenge in dirhodium­(II)-catalyzed MCRs (Scheme a).…”

Recent advances in the iron‐catalysed multicomponent reactions

“…Hantzsch dihydropyridine synthesis, [ 6,7 ] Biginelli reaction, [ 8,9 ] Passerini reaction, [ 10,11 ] Kabachnik‐Fields reaction, [ 12,13 ] Ugi reaction, [ 14,15 ] Gröbcke‐Blackburn‐Bienaymé reaction [ 16 ] etc. Transition metal catalysis also made its way into multicomponent reactions and different transition metals like Pd, [ 17 ] Cu, [ 18,19 ] Rh, [ 20 ] Au, [ 21 ] Ag, [ 22 ] Zn, [ 23 ] Fe [ 24,25 ] etc. have shown its applicability in MCRs.…”

Lesinurad – There are More Ways than One of Synthesizing the Drug

“…Although almost all of the chemistry examples presented in this review come from patent applications and have not been subjected to rigorous peer review, they might serve as an inspiration to organic chemists when tackling analogous synthetic problems. However, the readers are encouraged to pay particular attention to the very recent trends in using multicomponent reactions 39,40 and flow chemistry 41,42 to minimize the environmental impact and simultaneously achieve high yields of API.…”