摘要:
Di-(-)-menthylnona-2,7-diene-1,9-dioate (1) is converted to (-)-menthyl 3(S)-(N-benzylamino)-2(S)-(-)-menthoxycarbonyl)-1(S)-cyclohexane-1-acetate (2) with high diastereoselectivity upon treatment with the amide cuprate or zincate reagent Bn(TMS)NML(n) in the presence of ZnCl2. The folded orientation of the two enoate moieties in 1 is essential for this high asymmetric cyclization via tandem conjugate addition.