Development of wide scope asymmetric dipolar cycloaddition reactions and its synthetic applications

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A generality for diazo substrates was widely expanded in the Lewis acid catalyzed asymmetric cycloaddition reactions of cyclic carbonyl ylides generated from diazo carbonyl compounds. For example, highly enantioselective cycloadditions of a cyclic carbonyl ylide generated from a diazo compound containing a pyrrolidine ring could be successfully applied to an asymmetric total synthesis of (+)-Tashiromine. High levels of asymmetric induction were also found to obtain in the similar asymmetric cycloaddition reactions of cyclic azomethine ylides generated from diazo imine derivatives. The chiral Ni(II) complexes originally developed in our laboratory was also found to be effective catalysts for a wide scope of use in asymmetric cycloaddition reactions of nitrile oxides, diazo esters, and cyclic ylides.