g-C3N4/Metal Halide Perovskite Composites as Photocatalysts for Singlet Oxygen Generation Processes for the Preparation of Variable Oxidized Synthons

g-C3N4/metal halide perovskite composites were prepared and used for the first time as photocatalysts for in situ 1O2 generation to perform hetero Diels–Alder, ene and oxidation reactions with suitable dienes and alkenes. The standardized methodology was made applicable to a variety of olefinic substrates. The scope of the method is finely illustrated and the reactions afforded desymmetrized hydroxy-ketone derivatives, unsaturated ketones and epoxides. Some limitations were also observed, especially in the case of the alkene oxidations, and poor chemoselectivity was somewhere observed in this work which is the first application of MHP-based composites for in situ 1O2 generation. The experimental protocol can be used as a platform to further expand the knowledge and applicability of MHPs to organic reactions, since perovskites offer a rich variety of tuning strategies which may be explored to improve reaction yields and selectivities.