Cooperative Lewis Acid Catalysis for the Enantioselective C(sp<sup>3</sup>)–H Bond Functionalizations of 2-Alkyl Azaarenes

Rai, Pramod; Waiba, Satyadeep; Maji, Kakoli; Sahoo, Dibyaranjan; Maji, Biplab

doi:10.1021/acs.orglett.1c03387

Cited by 9 publications

(2 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Recently, our group proposed a new approach for the enantioselective C(sp 3 )–H bond functionalizations of 2-alkyl azaarenes via cooperative dual Lewis acid catalysis ( Scheme 18 ). 70 The strategy utilizes the activation of unactivated azaarene partners 112 by an achiral Lewis acid catalyst. Cooperatively, a chiral-at-iridium Lewis acid catalyst enables LUMO lowering of α,β-unsaturated 2-acyl imidazoles 35 to induce chirality.…”

Section: Chiral Lewis Acid Catalysismentioning

confidence: 99%

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

2021

Self Cite

View full text Add to dashboard Cite

The field of asymmetric catalysis has been developing to access synthetically efficacious chiral molecules from the last century. Although there are many sustainable ways to produce nonracemic molecules, simplified and unique methodologies are always appreciated. In the recent developments of asymmetric catalysis, chiral-at-metal Lewis acid catalysis has been recognized as an attractive strategy. The catalysts coordinatively activate a substrate while serving the sole source of chirality by virtue of its helical environment. These configurationally stable complexes were utilized in a large number of asymmetric transformations, ranging from asymmetric Lewis acid catalysis to photoredox and electrocatalysis. Here we provide a comprehensive review of the current advancements in asymmetric catalysis utilizing iridium and rhodium-based chiral-at-metal complexes as catalysts. First, the asymmetric transformations via LUMO and HOMO activation assisted by a chiral Lewis acid catalyst are reviewed. In the second part, visible-light-induced asymmetric catalysis is summarized. The asymmetric transformation via the electricity-driven method is discussed in the final section.

show abstract

Section: Chiral Lewis Acid Catalysismentioning

confidence: 99%

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Although the enantioselective construction of alkyl azaarenes having tertiary chiral centers has been attempted since 2012 by employing chiral Ni(II), Pd(II), and iminium ion catalysis (Scheme b), the first synthesis of the alkyl azaarenes containing α-quaternary stereocenters was reported by Palomo et al in 2016 (Scheme c) . Quaternary stereocenters are ubiquitous in natural products, but their asymmetric construction is still a significant challenge due to the steric aided lower reactivity of the reaction center.…”

mentioning

confidence: 99%

Asymmetric α-Functionalization of 2-Alkyl Azaarenes: Synthesis of Tertiary Fluorides Having Vicinal Stereogenic Centers

2021

View full text Add to dashboard Cite

An enantioselective approach for synthesizing fluorinated azaarenes containing vicinal quaternary−tertiary stereocenters is summarized. The chiral copper(I)−phosphine complex binds with the azaarenes followed by Michael addition to unsaturated acyl imidazoles, resulting in α-functionalized products with an excellent level of enantioselectivities (up to 99%), diastereoselectivities (>20:1), and yields (up to 97%). Furthermore, post-functionalization of the acyl imidazole part has also been demonstrated.

show abstract

Iridium‐Catalyzed Asymmetric Allylic Substitution of Methyl Azaarenes

et al. 2022

View full text Add to dashboard Cite

Herein, an Ir‐catalyzed asymmetric allylic substitution reaction of methyl azaarenes is described. Azaarenes such as (benzo)thiazole, oxazole, benzoimidazole, pyridine, and (iso)quinoline are all tolerated. The corresponding chiral azaarene derivatives are obtained in good yields with high enantioselectivity (up to 96 % yield and 99 % ee). The utilization of the Knochel reagent TMPZnBr⋅LiBr warrants the in situ formation of benzylic nucleophiles without additional activating reagents. 1H NMR studies suggested a two‐fold function of the Knochel reagent in this reaction. The synthetic utility of this method has been showcased by a concise enantioselective synthesis of an allosteric protein kinase modulator.

show abstract

Cooperative Lewis Acid Catalysis for the Enantioselective C(sp³)–H Bond Functionalizations of 2-Alkyl Azaarenes

Cited by 9 publications

References 49 publications

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

Asymmetric α-Functionalization of 2-Alkyl Azaarenes: Synthesis of Tertiary Fluorides Having Vicinal Stereogenic Centers

Iridium‐Catalyzed Asymmetric Allylic Substitution of Methyl Azaarenes

Contact Info

Product

Resources

About

Cooperative Lewis Acid Catalysis for the Enantioselective C(sp3)–H Bond Functionalizations of 2-Alkyl Azaarenes

Cited by 9 publications

References 49 publications

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

Recent Development of Bis-Cyclometalated Chiral-at-Iridium and Rhodium Complexes for Asymmetric Catalysis

Asymmetric α-Functionalization of 2-Alkyl Azaarenes: Synthesis of Tertiary Fluorides Having Vicinal Stereogenic Centers

Iridium‐Catalyzed Asymmetric Allylic Substitution of Methyl Azaarenes

Contact Info

Product

Resources

About

Cooperative Lewis Acid Catalysis for the Enantioselective C(sp³)–H Bond Functionalizations of 2-Alkyl Azaarenes