A General Route to Bicyclo[1.1.1]pentanes through Photoredox Catalysis

Strain release – an old tool for new transformations

This Feature Article provides an overview of research advances in the chemistry of spring-loaded molecules, focusing mainly on strain-release transformations.

Photoinduced strategies towards strained molecules

Photoinduced strategies towards radical reactions of [1.1.1]propellane and bicyclo [1.1.0]butanes by photoredox or metallaphotoredox catalysis have recently been disclosed, enabling controllable construction of 1,3-difunctionalized bicyclo[1.1.1]pentanes and cyclobutanes.

Silaboration of [1.1.1]Propellane: A Storable Feedstock for Bicyclo[1.1.1]pentane Derivatives

The silaboration of [1.1.1]propellane enables direct introduction of B and Si functional groups onto the bicyclo[1.1.1]pentane (BCP) scaffold in high yield under mild, additive-free conditions. The silaborated BCP can be obtained on a gram-scale in a single step without the need for column-chromatographic purification, and is storable and easy to handle, providing a versatile synthetic intermediate for BCP derivatives. We also describe various conversions of the C-B/C-Si bonds on the BCP scaffold, including development of a modified Suzuki-Miyaura cross-coupling reaction at the highly sterically hindered bridgehead sp³ carbon center of the BCP skeleton using a combination of highly activated BCP boronic esters, copper(I) oxide, and a PdCl₂ (dppf) catalyst system.

A radical exchange process: synthesis of bicyclo[1.1.1]pentane derivatives of xanthates

A new approach for the installation of the bicyclo[1.1.1]pentane unit on the xanthate moiety by means of a radical exchange process.