Dipolarophile, definition

This result allows us to propose a new definition of the normal addition it is the reaction which leads to the product corresponding to the above approach. This is characterized by a complementary electrostatic disposition of the dipole and the dipolarophile. 

An important factor which could influence asymmetric induction would be that cycloaddition is faster than catalyst decomplexation from the ylide. Although the precise mechanism remains unclear, the high levels of enantios-election in intermolecular cycloadditions with dipolarophiles provide definite support for the intermediacy of a chiral rhodium(II)-associated carbonyl ylide involved in the cycloaddition step. These examples indicate that metal-catalyzed dipole formation followed by cycloaddition has the potential to be a powerful method for asymmetric synthesis. 

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