Non-planar Boron Lewis Acids Taking the Next Step: Development of Tunable Lewis Acids, Lewis Superacids and Bifunctional Catalysts

Though boron Lewis acids are commonly adopting a trigonal planar geometry, a number of compounds were the trivalent boron atom is located in a pyramidal environment have been described. This review will highlight the recent developments of the chemistry and applications of non-planar boron Lewis acids, including a series of non-planar triarylboranes derived from the triptycene core. A thorough analysis of the properties and of the influence of the pyramidalization of boron Lewis acids on their stereoelectronic properties and reactivities are discussed on the basis of recent theoretical and experimental studies.