Asymmetric synthesis of cyclic ß-amino carbonyl derivatives by a formal [3 + 2] photocycloaddition.

Herein, a visible-light mediated strategy unlocking a family of cyclic ß-amino carbonyl derivatives bearing three contiguous stereogenic centres is introduced. The overall reactivity relies on the performance of the substrate-catalyst complex to assist both the enantiocontrol and the photoredox tasks. This transformation led to an enantioselective [3 + 2] photocycloaddition between coordinated α,ß-unsaturated acyl imidazoles and cyclopropylamine derivatives.

Asymmetric [2+2] photocycloaddition via charge transfer complex for the synthesis of tricyclic chiral ethers.

The asymmetric synthesis of chiral polycyclic ethers by an intramolecular [2+2] photocycloaddition is described. This process proceeded through a photocatalytically active iminium ion-based charge transfer (CT) complex under visible light irradiation. In this way a stereocontrolled [2+2] photocycloaddition is enabled leading to tricyclic products with good enantiomeric ratios.