Could London Dispersion Force Control Regioselective (2+2) Cyclodimerizations of Benzynes? YES: Application to the Synthesis of Helical Biphenylenes

In recent years, London dispersion interactions, which are the attractive component of the van der Waals potential, have been found to play an important role in controlling the regio- and/or stereoselectivity of various reactions. Particularly, the dispersion interactions between substrates and catalysts (or ligands) are dominant in various selective catalyzes. In contrast, repulsive steric interactions, rather than the attractive dispersion interactions, between bulky substituents are predominant in most of the noncatalytic reactions. Herein, we demonstrate the first example of London dispersion-controlled noncatalytic (2 + 2) cyclodimerization of substituted benzynes to selectively afford proximal biphenylenes in high yields and regioselectivities, depending on the extent of dispersion interactions in the substituents. This method can be applied for the synthesis of novel helical biphenylenes, which would be fascinating for chemists as these compounds are potential skeletons for ligands, catalysts, and medicines.

Automated summary

In recent years, it has been discovered that London dispersion interactions play an important role in controlling the regio- and stereo-selectivity of reactions. These interactions are dominant in selective catalysis, while repulsive steric interactions are predominant in noncatalytic reactions. A novel method utilizing London dispersion interactions has been developed for the synthesis of proximal biphenylenes, which have potential applications in ligands, catalysts, and medicines.