Synthesis 2021; 53(17): 2947-2960
DOI: 10.1055/a-1483-4575
special topic
Bond Activation – in Honor of Prof. Shinji Murai

Non-Directed β- or γ-C(sp3)–H Functionalization of Saturated Nitrogen-Containing Heterocycles

Shohei Ohno
,
Makoto Miyoshi
,
Kenichi Murai
,
Mitsuhiro Arisawa
This study was partially supported by the Platform Project for Supporting Drug Discovery and Life Science Research [Basis for Supporting Innovative Drug Discovery and Life Science Research (BINDS)] of the Japan Agency for Medical Research and Development (AMED) (Grant No. JP20am0101084), the Cooperative Research Program of ‘Network Joint Research Center for Materials and Devices’ from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), and Nagase Science Technology Foundation.


Abstract

Reactions that take place via C–H functionalization are valuable tools in organic synthesis because they can be used for the synthesis of target compounds and for the late-stage functionalization of bioactive compounds. Among these, non-directed C(sp3)–H functionalization reactions of saturated nitrogen-containing heterocycles have been developed in recent years. However, most of these lead to functionalization at the α-position relative to the heteroatom, and reactions at the β- or γ-positions are limited since these bonds are stronger and less electron-rich. Hence, in this review, we will discuss non-directed β- or γ-C(sp3)–H functionalization reactions of saturated nitrogen-containing heterocycles, which are of recent interest to medicinal chemists. These methods are attractive in order to avoid the pre-functionalization of substrates, and to reduce the number of synthetic steps and the formation of byproducts. Such non-directed β- and γ-C(sp3)–H functionalization reactions can be divided into enamine-intermediate-mediated processes and other reaction types described in this review.

1 Introduction

2 Non-Directed β-C(sp3)–H Functionalization of Saturated Nitrogen­-Containing Heterocycles via an Enamine Intermediate

2.1 Non-Directed β-C(sp3)–H Functionalization of Saturated Nitrogen­-Containing Heterocycles under Acidic, Basic or Thermal Conditions

2.2 Non-Directed β-C(sp3)–H Functionalization of Saturated Nitrogen­-Containing Heterocycles under Oxidative Conditions

2.3 Non-Directed β-C(sp3)–H Functionalization of Saturated Nitrogen­-Containing Heterocycles under Redox-Neutral Conditions

3 Strategies for Non-Directed β- or γ-C(sp3)–H Functionalization of Saturated Heterocycles Excluding Examples Proceeding via an Enamine Intermediate

4 Summary



Publication History

Received: 05 March 2021

Accepted after revision: 15 April 2021

Accepted Manuscript online:
15 April 2021

Article published online:
19 May 2021

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