Visible Light Induced Bifunctional Rhodium Catalysis for Decarbonylative Coupling of Imides with Alkynes

Abstract

Scheme 4. Mechanistic studies on reaction intermediate. Scheme 5. Proposed mechanism for decarbonylative coupling.

Photodissociation of the Product from a Transition-Metal Center Allows the Catalytic Cycle to Proceed: The Rhodium(I)-Catalyzed [2+2+1] Carbonylative Cycloaddition of Diynes

“…In addition, photoirradiation is also utilized in the dissociation of a strongly coordinating π-acidic ligand due to the dπ–pπ* back-bonding. − This corresponds to a simple ligand exchange via the formation of the coordinatively unsaturated species in the catalytic cycle. However, to the best of our knowledge, there is no example of a catalytic process in which photoirradiation is used to promote the release of the formed product, thus providing a vacant coordination site . Herein, we report on the first example of the effect of photoirradiation on such a catalysis, based on a strategy that the strongly coordinating product is dissociated as the result of photoirradiation.…”

Diverse reactivity of alkynes in C–H activation reactions

“…Recently, Chen et al reported an Rh-catalysed visible-light-induced decarbonylative coupling of imides 136 with alkynes 137 to form isoquinolones 138 (Scheme 47). 58 Careful examination of the reaction scope showed that aryl alkynes containing electron-withdrawing groups such as bromo- and trifluoromethyl were preferred over electron-donating groups such as methoxy. Additionally, symmetrical aliphatic alkynes are coupled consistently, giving products in moderate yields.…”

Micro-photo-flow reactor system for fused N-heteroaryl scaffold synthesis and late-stage functionalization of pyrazolopyridines

“…Based on our controlled experimental data and literature study, 7 b ,12,20 a plausible catalytic cycle has been proposed as demonstrated in Fig. S15 (ESI†).…”

“…11 Chen et al (2020) have recently reported a visible light induced rhodium catalysis for decarbonylative coupling of imides with alkynes under ambient conditions, where the group deployed any photocatalyst. 12 However, the batch photolysis reactions reported so far, in general, have suffered from several limitations like low quantum efficiency, minimal surface to volume ratio, inefficient mixing, longer reaction time and poor reaction selectivity. 10,13 In this regard, continuous flow technology has emerged and gained attention in recent years owing to its ability to overcome the above-mentioned issues.…”