Formation of Quaternary Stereogenic Centers by Copper-Catalyzed Asymmetric Conjugate Addition Reactions of Alkenylaluminums to Trisubstituted Enones
作者:Daniel Müller、Alexandre Alexakis
DOI:10.1002/chem.201302856
日期:2013.11.4
undergo asymmetric copper‐catalyzedconjugateaddition (ACA) to β‐substituted enones allowing the formation of stereogenic all‐carbon quaternary centers. Phosphinamine–copper complexes proved to be particularly active and selective compared with phosphoramidite ligands. After extensive optimization, high enantioselectivities (up to 96 % ee) were obtained for the addition of alkenylalanes to β‐substituted
Readily available alkenylalanes, arising from hydroalumination of unprotected terminal alkynes, have been directly employed for the copper-catalyzedasymmetricconjugateaddition (ACA) to β-substituted cyclic enones. The desired products, containing a quaternary stereogenic center, are generally obtained in good yields and enantioselectivities.