Reversal of Enantioselectivity between the Copper(I)- and Silver(I)-Catalyzed 1,3-Dipolar Cycloaddition Reactions Using a Brucine-Derived Amino Alcohol Ligand
作者:Hun Young Kim、Hui-Ju Shih、William E. Knabe、Kyungsoo Oh
DOI:10.1002/anie.200903479
日期:2009.9.21
The old switcheroo: The switch in the enantioselectivity of a reaction by using a single chiral source has been achieved using different metal binding modes of the chiral aminoalcohol 1 in the presence of CuI and AgI sources. Azomethine ylides were shown to undergo highly enantio‐ and diastereoselective 1,3‐dipolar cycloadditions with substituted tert‐butyl acrylates to provide both of the enantiomerically
Highly efficient catalytic asymmetric [3 + 2] cycloadditions using a chiral copper amide are reported. Compared with the chiral CuOTf/Et3N system, the CuHMDS system showed higher reactivity, and the desired reactions proceeded in high yields and high selectivities with catalyst loadings as low as 0.01 mol %.