Oxazaborolidines as Catalysts for Enantioselective Cycloadditions: Now [2+2]!

More and more applicable: The adduct of an oxazaborolidine and aluminum tribromide (see picture) turns out to be an efficient catalyst not only for enantioselective Diels–Alder reactions but now also for enantioselective [2+2] cycloadditions. The products are important enantiomerically pure building blocks for the synthesis of complex organic compounds.