Rhodium(II)‐Catalyzed Intramolecular Cycloisomerizations of Methylenecyclopropanes with N‐Sulfonyl 1,2,3‐Triazoles

Abstract

A novel rhodium(II)-catalyzed tandem cycloisomerization of methylenecyclopropanes (MCPs) with N-sulfonyl 1,2,3-triazoles is disclosed. The reaction produces a series of highly functionalized polycyclic N heterocycles via a rhodium imino carbene intermediate. A distinct feature of this divergent synthesis is that different types of substrates control the reaction pathways. Moreover, several interesting transformations of these products to construct diazabicyclo[3.2.1]octane derivatives are also reported.

Construction of Carbocycles from Methylenecyclopropanes

“…found that, catalyzed by [Rh 2 (Piv) 4 ], the dimerization reaction of N ‐sulfonyl‐1,2,3‐triazole‐substituted MCPs 100 occurred and produced the interesting highly functionalized polycyclic pyridine derivatives 101 bearing double fused CB rings [Eq. (43)] . The reaction was proposed to proceed via a rhodium azavinylcarbene intermediate.…”

Recent Advances in the Synthesis of Heterocycles and Related Substances Based on α‐Imino Rhodium Carbene Complexes Derived from N‐Sulfonyl‐1,2,3‐triazoles

“…[21] In this reaction, after an electrophilica ttack from the MCP,r ing expansion, and elimination of the catalyst, the diazoimine tautomer of 61 Upon heating, 65 can be transformed into its more thermodynamically stable isomer 60 through ar etro-Diels-Alder reaction process. For example, Shi and Tang reported that tandemc ycloisomerization of methylenecyclopropanes (MCPs) with N-sulfonylt riazoles can afford polycyclic N-heterocycle 60 (Scheme12).…”

“…For example, Shi and Tang reported that tandemc ycloisomerization of methylenecyclopropanes (MCPs) with N-sulfonylt riazoles can afford polycyclic N-heterocycle 60 (Scheme12). [21] In this reaction, after an electrophilica ttack from the MCP,r ing expansion, and elimination of the catalyst, the diazoimine tautomer of 61 Scheme8.Synthesis of indole-fused polycycles.…”

Pentannulation of Heterocycles by Virtue of Precious Metal Catalysis

“…Shi and co‐workers elegantly demonstrated the efficiency of Rh II in the synthesis of polycyclic compounds 139 through intramolecular cycloisomerizations of 138 (Scheme ) . Besides being diastereoselective, this transformation is very general; neither the electronic properties of the aromatic ring nor different sulfonyl groups did significantly impact the yield.…”