Ir-Catalyzed Enantioselective Formal C–H Conjugate Addition of Pyrrole and Indoles to α,β-Unsaturated Carbonyl Compounds

Abstract

The chiral Ir­(I)-catalyzed intermolecular reaction of N-carbamoylpyrrole and indole derivatives with α,β-unsaturated carbonyl compounds such as crotonates proceeded with high enantioselectivity. The obtained chirally functionalized pyrroles and indoles are formal C–H conjugate adducts. The reaction mechanism was studied by deuterium labeling experiments.

Ir-Catalyzed Remote Functionalization by the Combination of Deconjugative Chain-Walking and C–H Activation Using a Transient Directing Group

“…On the basis of the results of these deuteration experiments and previous reports, ,, a plausible mechanistic pathway for the present hydroarylation along with chain-walking is depicted in Figure . Oxidative addition of the ortho -C–H bond of 1a to the Ir­(I) center gives iridium hydride complex A .…”

“…In contrast, our group reported an array of Ir-catalyzed transformations initiated by C–H activation . As a continuation of these studies, we sought to combine C–H activation and chain-walking.…”

Tail‐To‐Tail Stereoselective Dimerization of Acrylate Derivatives via Iridium‐Catalyzed Vinylic sp2 C−H Activation

“…In all of these cases, they are used as acceptors for hydroarylation and hydroalkenylation, and we did not consider their potential as donors via vinylic sp 2 C−H activation. Recently, we reported the first enantioselective cross‐coupling of electron‐deficient alkenes initiated by vinylic sp 2 C−H activation [14i] . During the screening of acrylate derivatives in that study, we happened to obtain a significant amount of a dimer of phenyl acrylate.…”

Transition-metal-catalyzed C–H bond alkylation using olefins: recent advances and mechanistic aspects

“…A few years later, the same group reported an efficient protocol for enantioselective hydroarylation of electron deficient alkene 84e compounds with N -carbamoylpyrrole and indole derivatives 84d under chiral Ir( i ) catalysis conditions (Scheme 84B). 157 The protocol well tolerated a diverse range of enoates, enones, and Michael acceptors, affording good to excellent yields and enantioselectivity.…”