A Convenient One‐Pot Route to Screw‐Shaped [5]Azahelicenes via Rhodium(III)‐Catalyzed Multiple C−H Bond Activation

Abstract

A convenient rhodium(III)-catalyzed cascade reaction of 7-azaindoles and alkynes through multiple C-H bond activation for the synthesis of unique [5]azahelicenes has been developed. The optical property of these screw-shaped helicene derivatives could be further utilized in electronic devices to recognize mercury ions.

A comprehensive overview of directing groups applied in metal-catalysed C–H functionalisation chemistry

“… 972 , 973 The reaction with alkynes, occurring as previously reported for other DGs, was also investigated ( Scheme 157J and K ). 974 , 975 Interesting in this respect is the reaction with 3 equiv. of alkyne, which results in both ortho olefination–cyclisation and arene homologation, ultimately furnishing azahelicenes, interesting compounds for their fluorescent properties.…”

“…of alkyne, which results in both ortho olefination–cyclisation and arene homologation, ultimately furnishing azahelicenes, interesting compounds for their fluorescent properties. 975 …”

Regioselective Direct C‐Alkenylation of Indoles

“…[132] This approach is also usefulf or the preparation of azahelicene derivatives adoptingd ifferent reaction conditions. [133] The reaction is catalyzed by [Cp*Rh(CH 3 CN) 3 ](SbF 6 ) 2 and affords the corresponding products from modestt os atisfactory yields (17-82 %).…”

“…Recently, using the same catalyst 1‐aryl‐7‐azaindoles have been converted into similar tetracyclic compounds . This approach is also useful for the preparation of azahelicene derivatives adopting different reaction conditions . The reaction is catalyzed by [Cp*Rh(CH 3 CN) 3 ](SbF 6 ) 2 and affords the corresponding products from modest to satisfactory yields (17–82 %).…”

Rhodium(III)-Catalyzed Regioselective C(sp2)–H Functionalization of 7-Arylpyrazolo[1,5-a]pyrimidines with Dioxazolones as Amidating Agents

“…In many cases, transition metal-catalyzed C–H bond functionalization proceeded with either traceless or transient directing group . Meanwhile, the coordinating moiety of certain substrate could also direct the construction of various biologically important molecules . However, in chemically stable molecules lacking of strong coordinating ability, both insertion and removal of directing group are proven difficult.…”