Constructing Heterocycles by Visible Light Photocatalysis

Heterocycles are widely spread in natural products and in many bioactive compounds, as well as in a variety of fine chemicals. Synthesis through catalysis is always an advantageous strategy and today it is difficult to consider an approach to a target molecule without the inclusion of a catalytic step. Moreover, it is indeed almost a required characteristic for all the synthetic transformations in line with the principles of green chemistry and sustainable processes. Chemical transformations via visible light photocatalysis are emerging strategies that meet the increasing demand for more sustainable chemical processes. Up to date, several visible light approaches have been successfully applied to various organic transformations. Moreover, potential advantages are envisaged in this highly active new field. This review gives a brief overview of methods based on visible-light photoredox catalysis that have been developed for the synthesis of heterocycles using transition metal catalysts and organic catalysts. Only works in which at least one heterocycle is constructed are included, leaving the vast area of functionalization of heterocycles for other reviews.