Catalytic Asymmetric Diamination of Styrenes

An
enantioselective catalytic vicinal diamination of styrenes is
reported, which proceeds under entirely intermolecular reaction control.
It relies on a chirally modified aryliodine­(I) catalyst and proceeds
within an iodine­(I/III) manifold with conventional 3-chloroperbenzoic
acid as a terminal oxidant. An environmentally benign solvent combination
not only adds to the attractiveness of the process but also slows
down the rate of the undesired background reaction. A total of 30
examples are presented, which consistently provide high enantiomeric
excesses in the range 91–98%.