Rhodium‐Catalyzed Cascade Reactions using Diazo Compounds as a Carbene Precursor to Construct Diverse Heterocycles

• Published in: Asian journal of organic chemistry 2022-01, Vol.11 (1), p.n/a
• Main Authors: Soam, Pooja, Kamboj, Priya, Tyagi, Vikas
• Format: Article
• Language: English
• Subjects: Carbazoles; Carbene; Carbenes; Cascade chemical reactions; Cascade reactions; Catalysts; Chemical reactions; Copper; Diazo compounds; Heterocyclic compounds; Indoles; Iron; Organic chemistry; Palladium; Precursors; Rhodium; Transition metals
• ISSN: 2193-5807; 2193-5815
• DOI: 10.1002/ajoc.202100570

Diazo compounds being used as a precursor of carbenes in synthetic chemistry by reacting them in different manners like photochemically, thermally or with metal catalysts. Further, the use of metals as a catalyst generates metallocarbenes in the reaction medium which has similar reactivity like free carbenes. In this context, a number of transition metal catalysts like Rh, Pd, Cu, Ru, Ir, Fe etc. have been employed to generate metal bound carbenes in the reaction medium. Among various metal catalyst, rhodium being used extensively in industry as well as in academia to catalyze a number of cascade transformations containing carbene insertion/transfer. In this review, we are covering the efforts made in the last five years toward the synthesis of highly important heterocyclic compounds such as isoquinoline, indoles, isocoumines, oxazoles, carbazoles etc. through rhodium catalysed cascade reactions containing carbene transfer as the vital step. This review features the recent advancement made in the area of rhodium catalyze‐cascade reactions consisting of carbene transfer as a vital step. In this context, a diverse range of nitrogen or oxygen containing heterocycles have been prepared using diazo compounds or their equivalents as a precursor of carbene.