Stereocontrol through Catalytic Enantioselective C sp2 H and C sp3 H Alkylation From Bifunctional Organocatalysis to Iridium Catalysis

Abstract

This thesis, entitled Stereocontrol through Catalytic Enantioselective C(sp2)and#8722;H and C(sp3)and#8722;H Alkylation: From Bifunctional Organocatalysis to Iridium-Catalysis primarily deals with the development of various catalytic enantioselective C(sp2)and#8722; and C(sp3)and#8722; alkyl and allyl bond forming reactions. In Chapter 1, we have described a new and general approach for the enantioselective synthesis of monosubstituted norbornenoquinones based on C(sp2)and#8722;H alkylative desymmetrization of meso norbornenoquinones. Catalyzed by a bifunctional tertiary amino(thio)urea derivative, and utilizing air-stable and inexpensive nitroalkanes as the alkylating agents, this operationally simple protocol delivers synthetically versatile benzoquinone-fused tricyclic compounds, containing at least four contiguous stereogenic centers remote from the reaction site, with excellent enantioselectivities (up to 99:1 er). In Chapter 2, we have discussed the development of the first Ir-catalyzed enantioselective vinylogous allylic alkylation of a coumarin derivative. This Ir/phosphoramidite catalyzed reaction utilizes easily accessible linear allylic carbonates as the allylic electrophile to install an unfunctionalized allyl group. This protocol delivers synthetically versatile and#61543;-allylcoumarins in exclusively branched-selective manner generally in high yields with an excellent level of enantioselectivity (up to 99:1 er). In Chapter 3, we have shown the first enantioselective vinylogous allylic alkylation of 4-methylquinolones. This iridium-catalyzed reaction introduces an allyl group at the and#947;-position of 4-methyl-2-quinolones with exclusive branched selectivity and excellent level of enantioselectivity (up to 99:1 er). This in turn allows for the enantioselective synthesis of and#947;-allylquinolines and related nitrogenous heterocycles. This is the first application of 4-methylquinolones in an enantioselective transformation...