Recent Advances in Iminyl Radical Cyclizations

Abstract

Iminyl radical cyclizations have emerged as important tools for constructing five- and six-membered nitrogen-containing heterocycles. Both aromatic and nonaromatic ring systems are readily accessible from a variety of radical precursors. This short review focuses on recently discovered iminyl radical cyclizations. Methods that use heat, transition metals, or oxidants to generate the radicals are discussed, as are protocols employing either UV irradiation or visible light. Many of these newly developed procedures should be quite useful to the organic synthesis community due to their utilization of mild and convenient conditions.

1 Introduction

2 Generation of Iminyl Radicals via Thermolysis, Transition Metals, or Oxidants

2.1 Formation of Five-Membered Rings

2.2 Formation of Six-Membered Rings

3 Generation of Iminyl Radicals via UV Irradiation

3.1 Formation of Five-Membered Rings

3.2 Formation of Six-Membered Rings

4 Generation of Iminyl Radicals via Visible Light Irradiation

4.1 Formation of Five-Membered Rings

4.2 Formation of Six-Membered Rings

5 Conclusion

Key words

cyclization - heterocycles - nitrogen-centered radicals - photochemistry - radical reactions

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