Chiral tertiary alcohols from a trans-1-arenesulfonyl-amino-2-isoborneolsulfonylaminocyclohexane-catalyzed addition of organozincs to ketones

The catalytic enantioselective addition of different organozinc reagents, such as alkyl, or in situ generated aryl, allyl, alkenyl and alkynyl derivatives to simple aryl ketones, was accomplished using titanium tetraisopropoxide and chiral ligands derived from 1-arenesulfonylamino-2-isoborneolsulfonylamidocyclohexane, giving the corresponding tertiary alcohols with enantioselectivities up to >99%. A simple and efficient procedure for the synthesis of the disulfonamide ligands used is described.

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N-{2-(2-Hydroxy-7,7-dimethylbicyclo[2.2.1]hept-1-ylmethanesulfonylamino)cyclohexyl}-4-methylbenzenesulfonamideC23H36N2O5S2Ee = 100%[α]D25=+7.8 (c 2.1 CHCl3)Source of chirality: (+)-10-camphorsulfonyl chloride

N-{2-(2-Hydroxy-7,7-dimethylbicyclo[2.2.1]hept-1-ylmethanesulfonylamino)cyclohexyl}-4-methoxybenzenesulfonamideC23H36N2O6S2Ee = 100%[α]D25=+9.2 (c 0.8 CHCl3)Source of chirality: (+)-10-camphorsulfonyl chloride