Palladium-catalyzed direct C(sp³)–H arylation of indole-3-ones with aryl halides: a novel and efficient method for the synthesis of nucleophilic 2-monoarylated indole-3-ones

Abstract

A novel and efficient method for the synthesis of nucleophilic 2-monoarylated indole-3-ones via palladium-catalyzed direct C(sp3)–H arylation of indole-3-ones with aryl halides has been developed.

Asymmetric oxidative Mannich reactions promoted by photocatalysis and electrochemistry

“…19 The structural motif of C2-quaternary indolin-3-one has attracted the attention of synthetic chemists due to its presence in several bioactive natural products and drug molecules. 20 Under the optimized conditions, which consisted of Ru(bpy) 3 Cl 2 as a photocatalyst, l -proline or d -proline as an organocatalyst, 2,6-lutidine as an additive, ethanol as a solvent, and blue LEDs as the light source, under an oxygen atmosphere, the desired products were obtained with 20–92% yields, 90–99% ee and 5:1 to 20:1 dr. Twenty-six examples were reported. Various substituents on indole and both chain and cyclic aliphatic ketones were well tolerated.…”

One‐Pot Asymmetric Oxidative Dearomatization of 2‐Substituted Indoles by Merging Transition Metal Catalysis with Organocatalysis to Access C2‐Tetrasubstituted Indolin‐3‐Ones

“…C2‐tetrasubstituted indolin‐3‐one skeletons represent an important class of structural motifs, which are existed in various natural products and biologically active molecules, [1,10b–c] such as (−)‐Isatisine A, [1a] Aristotelone, [1b–c] Austamide [1d] and Fluorocarpamine, [1e] etc . In addition, these skeletons can also be used as key intermediates in the total synthesis of many natural products, [1e,g–i,2,10b] such as Hinckdentine A, [2a–c] Lapidilectine B [2d–e] and (−)‐Trigonoliimine C, [2f–i] etc . (Figure 1).…”

“…Therefore, although significant advances have been made in the asymmetric synthesis of the valuable C2‐tetrasubstituted indolin‐3‐one skeletons based on asymmetric oxidative dearomative cascade reactions from 2‐substituted indoles, it should be noted that mild, environmentally friendly and efficient synthetic methods still need to be further developed for constructing the diversity of C2‐tetrasubstituted indolin‐3‐ones. With our ongoing interest in the study of indolin‐3‐one chemistry, [10] especially the structure of C2‐tetrasubstituted indolin‐3‐ones, [10a–c] we herein describe a one‐pot approach for the asymmetric synthesis of C2‐tetrasubstituted indolin‐3‐ones 3 from 2‐substituted indoles 1 via merging transition metal catalysis with organocatalysis. This strategy using commercially available CuI as metal‐catalyst, O 2 as green oxidant and proline as organocatalyst, undergo two processes including oxidative dearomatization of 2‐substituted indoles and proline‐promoted asymmetric Mannich reaction (Scheme 1e).…”

“…Due to the importance in structure, biological activity and synthetic applications, much efforts have been devoted to the synthesis of these valuable C2‐tetrasubstituted indolin‐3‐one skeletons [1e–i,2c,3–5,8–9,10a–c] . Up to now, some asymmmetric synthetic methods based on the reactivity of indolin‐3‐ones at C2 positions [4–5,10a–c] and annulation of nitroalkynes with indoles [3] have been developed to construct these C2‐ tetrasubstituted indolin‐3‐one skeletons, however, these reported methods usually require the multi‐step synthesis of starting materials or have limited substrate scope. Therefore, more efficient approach for the construction of structurally diverse C2‐tetrasubstituted indolin‐3‐ones is still highly desired.…”

Organocatalytic Asymmetric α-Sulfenylation of 2-Substituted Indolin-3-ones: A Strategy for the Synthesis of Chiral 2,2-Disubstituted Indole-3-ones with S- and N-Containing Heteroquaternary Carbon Stereocenter

“…In 2017, two examples of organocatalytic asymmetric amination of 2-substituted indolin-3-ones were reported by Lu et al and Subba Reddy et al (Scheme a), respectively. , However, there were no reports on the direct asymmetric α-sulfenylation of nucleophilic indole-3-ones with electrophilic sulfur reagents. With our ongoing interest in the study of organocatalysis and indolin-3-one chemistry, , we envisaged that the indolin-3-one skeletons possessing S- and N-containing heteroquaternary carbon stereocenters at the C2 positions could be created via a organocatalytic α-sulfenylation of indolin-3-ones 1 (Scheme b).…”