Asymmetric Cycloaddition Reaction Of Allenoate Catalyzed By N-Acyl Aminophosphine

This dissertation focuses on the development of novel bifunctional N-acyl aminophosphine catalysts and their applications in asymmetric allenoates-involved annulation reactions.1. A series of novel bifunctional N-acyl aminophosphine catalysts were synthesized from chiral a-amino acid, and their catalytic capacity were evaluated in the asymmetric [3+2] cycloaddition between allenoates and dual activated olefins. After a systematic optimization on catalyst structure by varing H-bonding donors and chiral backbones of the catalysts, the L-isoleucine derived N-acyl aminophosphine proved to be the catalyst of choice, affording multifunctional chiral cyclopentenes with exclusive regioselectivity, good to excellent enantioselectivies and yields. The catalyst also exhibits good catalytic activity in the deracemization of y-substituted racemic allenoate by the [3+2] reaction, albeit with somewhat decreased stereoselectivities.2. The above developed bifunctional N-acyl aminophoshpine catalysts were successfully applied to the asymmetric [4+2] cycloaddition between a-substituted allenoates and N-tosylaldimines, which allow facile accesses to a variety of optically active tetrahydropyridine derivatives. This operationally simple catalytic system could provide valuable complementary results to those of the known monodentate phosphine system.3. An asymmetric organocatalytic [4+2] cycloaddition between a-substituted allenoates and dual activated olefins was achieved by using bifunctional the above N-acyl aminophoshpine catalysts. The annulation providing a range of synthetically valuable cyclohexene structures bearing three contiguous chiral centers with good to excellent diastereoselectivities and enantioselectivities. The use of2-cyano acrylate derived olefins not only improved the reaction’s diastereoselectivity significantly but also led to the first successful incorporation of an electrophile derived from an aliphatic aldehyde into this reaction.4. Phosphine-catalyzed chemoselective reactions of EWG-activated carbonyl compound and a,y-substituted allenoates were realized by judicious selection of the catalysts and reaction conditions. The chemoselectivity of the reaction mainly depended on the nucleophilicity of the phosphine catalyst:the use of (p-MeOC6H4)3P led to tetrahydrofuran derivatives through a [3+2] cycloaddition process with good E/Z selectivity, while the use of more nucleophilic Bu3P afforded conjugative olefins via a one-step addition reaction.