Through-Space 1,4-Palladium Migration and 1,2-Aryl Shift: Direct Access to Dibenzo[<i>a</i>,<i>c</i>]carbazoles through a Triple CH Functionalization Cascade
作者:Samir Kumar Bhunia、Arghya Polley、Ramalingam Natarajan、Ranjan Jana
DOI:10.1002/chem.201503474
日期:2015.11.16
A palladium‐catalyzed expeditious synthesis of dibenzofused carbazoles from readily available 2‐arylindoles and diaryliodonium salts is reported. Interestingly, after the electrophilic C3 palladation of indole, an unexpected “through‐space” 1,4‐palladium migration to the 2‐aryl moiety, by remote CH bond activation followed by CH arylation with diaryliodonium salt, and an unprecedented 1,2‐aryl shift
The palladium-catalyzed cyclization of 2-(2-bromoaryl)-3-arylindoles provides a new versatile approach to dibenzo[a,c]carbazoles. The reaction tolerates a variety of useful substituents including chloro, nitro, ether, cyano, keto, and ester groups.