Substitution Of Amino Groups In Alkylamines

Substitution reaction is one of important types of organic chemical reactions, nature of which are chemical bonds cleavage and formation. Substitution reaction cleavaging carbon-heteroatom bonds to form new carbon-carbon, carbon-heteroatom, carbon-hydrogen bonds are always the important research areas of organic chemistry. Because of the larger bonding energy of sp3C-N bond and the weaker leaving ability of N comparing with C-X, C-O and C-P bonds, the research of new method for cleavage or enantioselective cleavage of sp3C-N bond of alkylamine is still one of the challengs of organic synthetic methodology. In this dissertation, we present new efficient and economical reactions for cleavage or enantioselective cleavage of sp C-N bonds of allylamine and benzylamine catalyzed by palladium or phosphoric acid under acidic conditions. These studies significantly extend the applications of alkylamines as synthetic intermediates in organic synthesis.First, we report primary allylic amine as a new type of allylic electrophile. In contrast with allylic halides, esters, carbonates, phosphates and alcohols, the transition metal-catalyzed allylation reactions of primary allylic amines with nucleophiles have high yield, high atom economy, high stereoselectivity and regioselectivity, and good tolerance of water. It provides new effective methods for synthesis of achiral and chiral allylic compounds.A versatile method for the preparation of allylic sulfones via the reaction of primary allylic amines with sodium alkylsulfinates catalyzed by palladium complex catalysts has been developed with high atom economy. Asymmetric synthesis of allylic sulfones from a-chiral primary allylic amines is also achieved with high enantioselectivity by chirality transfer.Palladium-catalyzed allylation of hypophosphorous acid or H-phosphinic acids with primary allylic amines has been developed. In the transformation, hypophosphorous acid works as both nucleophile and additive, no extra additive is required and the products are obtained in excellent yields. It is convenitent that aqueous solution of hypophosphorous acid is used directly as reactant.Substitution reaction of N-(3-indoly)methylic sulfonamides with mercaptans via enantioselective sp3C-N bond cleavage catalyzed by chiral phosphoric acid has also been developed. In the presence of10mol%of a chiral phosphoric acid, a variety of racemic N-benzylic sulfonamides having N-(3-indolyl)methyl groups smoothly undergo kinetic resolution with benzyl thiol at0℃or at room temperature and the remaining sulfonamides are recovered in moderate to excellent yields and with excellent ee.