Asymmetric Allylation Reaction Of Styrene Oxide, Baylis-Hillman Reactions, And Aldol Reactions Catalyzed By Organocatalysts

一.The asymmetric ring-opening allylation of styrene epoxides promoted by chiral acidsThe ring-opening allylation of styrene epoxides by allyl bromide promoted by chiral acids, tin, was investigated under various conditions, such as different solvents, temperature and catalysts. Moderate yields and low enantiomeric excess were obtained.二.Synthesis and application of chiral amine from L-proline in the asymmetric Baylis-Hillman ReactionChiral catalysts were prepared conveniently from L-proline, and applied in asymmetric Baylis-Hillman reaction to study the relationship between catalyst structure and enantioselectivity. The selectivities of asymmetric Baylis-Hillman reaction in PEG(400) were detected, and moderate yield, low selectivities were achieved by using 30 mol% catalyst.三. Asymmetric Direct Aldol Reaction Promoted by (4S)-Phenoxy-(S)-Proline in Ionic Liquid [bmim]PF₆Room temperature ionic liquid [bmim]PF₆ was evaluated for recycling an organocatalyst (4S)-phenoxy-(S)-proline for direct asymmetric Aldol reactions. The desired Aldol products were obtained with good yields (up to 96.0%) and enantioselectivities (up to 86.3%); isolation of the products by simple extraction allowed recycling of the ionic liquid containing the immobilized catalyst in subsequent reactions without significant decrease of yields and enantioselectivities.