Halogen Bonding in Organocatalysis

Besides the conventional solid-state studies, recently halogen bonding has shown considerable progress in organocatalysis. Much resemblance to the well-established noncovalent interaction -hydrogen bonding has permitted efficient activation of several anionic and neutral organic functional groups and also aromatic p-systems through its direct or indirect involvement. In addition to the quenching of XB adducts with halide traps, comparatively weak binding of organic functional groups allowed regeneration of the XB donors and made catalytic processes possible. Nevertheless, expansion of its scope for catalyzing synthetically more useful and enantioselective reactions still needs further attention.