Heterocycle Formation via Palladium-Catalyzed C–H Functionalization

Abstract

Heterocyclic compounds are ubiquitous in natural products, pharmaceuticals, and agrochemicals. Therefore, the design of novel protocols to construct heterocycles more efficiently is a major area of focus in organic chemistry. In the past several years, cyclization reactions based upon palladium-catalyzed C–H activation have received substantial attention due to their capacity for expediting heterocycle synthesis. This review discusses strategies for heterocycle synthesis via palladium-catalyzed C–H bond activation and highlights recent examples from the literature.

1 Introduction

2 Intramolecular Cyclization via C–C Bond Formation

2.1 Arene/Arene Coupling

2.1.1 C–H Arylation with Aryl Halides

2.1.2 C(sp²)–H/C(sp²)–H Coupling

2.2 Arene/Alkene Coupling or Arene/Alkyne Coupling

2.2.1 Arene/Alkene Coupling

2.2.2 Arene/Alkyne Coupling

2.3 Arene/Alkane Coupling

2.3.1 C(sp²)–H Alkylation with Alkyl Halides

2.3.2 C(sp³)–H Arylation with Aryl Halides

2.3.3 C(sp²)–H/C(sp³)–H Coupling

3 Intramolecular Cyclization via C–N Bond Formation

4 Intramolecular Cyclization via C–O or C–S Bond Formation

5 Incorporation with Carbon Monoxide

6 Incorporation with Isonitrile

7 Incorporation with Olefin

8 Conclusions

Key words

heterocycle - C–H activation - arylation - alkylation - amination - carbonylation - olefination

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