Rhodium‐Catalyzed Enantioselective Reductive Arylation: Convenient Access to 3,3‐Disubstituted Oxindoles

Abstract

A rhodium-Josiphos(L*) catalyzed enantioselective intramolecular hydroarylation reaction is described. The reductive cyclization of o-bromoaniline-derived acrylamides provides convenient access to 3,3-disubstituted oxindoles in good yields and with excellent enantioselectivity across a range of substrates. We propose that the key cyclization proceeds via a rhodium(III) intermediate. Overall, this method represents an unusual mode of reactivity for rhodium catalysis and is complementary to palladium(0)-catalyzed α-arylation methods.

Palladium‐Catalyzed Asymmetric Intramolecular Reductive Heck Desymmetrization of Cyclopentenes: Access to Chiral Bicyclo[3.2.1]octanes

“…On the basis of the above mentioned results and previous literature, a proposed mechanism of this reaction is shown in Scheme . Firstly, 1 a undergoes oxidative addition of the active Pd catalyst to give the cationic Pd II intermediate A .…”

“…However, because of the high propensity of the β‐hydride elimination pathway (Heck reaction), the asymmetric version of the reductive Heck reaction is still in its infancy. Prior works on the asymmetric intramolecular reductive Heck reactions of either 1,1‐disubstituted olefins or 2‐substituted indoles have been realized by the groups of Diaz, Jia,, Zhu,, Lautens, Tong, and Zhang (Scheme a). In these elegant works, the in situ generated alkylpalladium intermediates were efficiently trapped by the hydride donors to deliver the asymmetric reductive Heck products because they lacked the β‐hydrogen.…”

Enantioselective Intermolecular Murai-Type Alkene Hydroarylation Reactions

“…Reductive processes, in which a prefunctionalized aryl substrate is used, have been pursued as an alternative approach. [72][73][74] List and co-workers have disclosed intramolecular hydroheteroarylations of non-polarized alkenes with indole moieties (Scheme 4, C). 75 This method uses a chiral Brønsted acid catalyst (L2) to produce tertiary carbocations from alkenes in situ, and provides a broad range of tetrahydrocarbazoles possessing quaternary stereocenters.…”

Bimetallic Cooperative Catalysis for Decarbonylative Heteroarylation of Carboxylic Acids via C‐O/C‐H Coupling

“…In the context of biaryl synthesis, rhodium catalysis has represented a particularly robust strategy for the construction of C−C bonds via direct C‐H activation with the assistance of directing groups [26–29] . Rhodium‐catalyzed decarbonylative arylation of carboxylic acids via C‐H coupling with the assistance of directing groups has been reported (Figure 1 D).…”