Enantio- and diastereoselective michael reactions of silyl enol ethers and chalcones by catalysis using a chiral quaternary ammonium salt.
[reaction: see text] N-(9-Anthracenylmethyl)dihydrocinchonidinium bromide (1) is an effective catalyst for enantioselective Michael additions to chalcones, as shown in the above example, using toluene/50% aqueous KOH biphasic conditions at -20 degrees C.
Zhang
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Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, Massachusetts 02138, USA.
Corey
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