Directed Ring Opening Reaction Of Epoxies And Aziridines By Lewis Acid Catalysis

Amino alcohols are ubiquitous motifs in natural products and drug molecules,and thus represent a vital class of compounds with high synthetic value.Nucleophilic ringopening reaction of epoxy alcohols or aziridine alcohols provides one of the most simple and efficient approaches to synthesize amino alcohols.These ring opening reactions are bestowed with numerous advantages including simple operation,mild conditions,and inexpensive catalysts,and are thus of great significance to organic synthesis.This dissertation is divided into three sections and focuses on Lewis acidcatalyzed ring-opening reactions of epoxy alcohols and aziridinyl alcohols.Section one:Boronic Acid-Catalyzed Regioselective Aminolysis of 3,4-Epoxy AlcoholsRelying on the directing effect of hydroxyl group,we achieve the regioselective aminolysis of 3,4-epoxy alcohols using low-priced and readily available 3,4,5trifluorophenylboronic acid as the catalyst,wherein the successful substrates include challenging terminal epoxies and aryl epoxies.This reaction provides a feasible method for the synthesis of y-amino alcohols.Section two:Nickel-Catalyzed Regio-and Enantioselective Aminolysis of 3,4Epoxy Amides and Esters.Under the catalytic system consisting of Ni(OTf)2 and a chiral bipyridine,we accomplished regio-and enantioselective ring-opening of 3,4-epoxy esters/amides with aromatic amines as the nucleophiles.With mild conditions and simple precursors,this reaction constitutes a simple and effective method to synthesize y-amino acid derivatives.Section three:Zinc-Catalyzed Hydroxyl-Directed Regioselective Ring Opening of Aziridines in SN2 Reaction PathwayWe developed a regioselective ring-opening reaction of 2,3-aziridinyl alcohols using Zn(OTf)2 as a catalyst and aromatic amines or thiophenols as nucleophiles.The directing effect of the hydroxyl group leads to nucleophilic attack at the C-3 position of 2,3-aziridinyl alcohols.This strategy provides an efficient route for the synthesis of amino alcohols.Furthermore,we synthesize a series of regio-and diastereomerically pure vicinal diamines through derivatizations of the ring opening products.