Enantioselective molybdenum-catalyzed allylic alkylation using chiral bisoxazoline ligands

[GRAPHICS] A series of chiral C-2-symmetric bisoxazolines with trans-1,2-diaminocyclohexane backbones was synthesized. In View of the promising results obtained by Trost with analogous bispyridine ligands, we tested our new ligands in the enantioselective molybdenum-catalyzed allylic alkylation of 1- and 3-monosubstituted allylic substrates, Enantiomeric excesses of up to 98% and branched/linear ratios of up to 11:1 were obtained with (E)-3-(n-alkyl)allyl carbonates. (E)-3-Phenoxyallyl acetate gave a branched/linear ratio of >20:1 and an ee of 98%.