Asymmetric Synthesis of Tertiary α-Hydroxylation-Cyclopentanones via Synergetic Catalysis of Chiral-at-Metal Rhodium(III) Complexes/Pyrrolidine.

Catalytic and asymmetric domino Michael/aldol reaction of 1,2-dicarbonyl compounds with α,ß-unsaturated ketones under the synergetic catalysis of chiral-at-metal rhodium complexes and pyrrolidine to deliver tertiary α-hydroxylation-cyclopentanones (45-89% yields with 81-99% ee and up to >20:1 dr) bearing three contiguous stereogenic centers had been established. Moreover, the scalability and practical utility of this protocol were well demonstrated by employing a gram-scale reaction and some representative transformations.

Diastereoselective synthesis of N-aryl tetrahydroquinolines and N-aryl indolines by the tandem reaction of arynes.

A tandem reaction of arynes with α- or ß-amino ketones has been revealed. Arynes react with ß-amino ketones through a cascade insertion-cyclization process to afford N-aryl tetrahydroquinolines in good yield with excellent anti-selectivity. Meanwhile, the coupling of arynes with α-amino ketones produces multisubstituted indolines in high yield with syn-selectivity. A quaternary carbon center can be constructed in this process, and the reaction can be easily scaled up.

NHCs catalyzed hydrophosphonylation of α-ketoesters and α-trifluoromethyl ketones.

N-Heterocyclic carbenes catalyzed hydrophosphonylation reaction of α-ketoesters and α-trifluoromethyl ketones was developed. Under the catalysis of 10 mol% IPr, α-ketoesters or α-trifluoromethyl ketones reacted with dialkyl phosphites to provide quaternary α-hydroxyphosphonates in good to excellent yield.

Asymmetric Synthesis of Chiral Cyclopropanes from Sulfoxonium Ylides Catalyzed by a Chiral-at-Metal Rh(III) Complex.

An enantioselective cyclopropanation reaction of sulfoxonium ylides with ß,γ-unsaturated ketoesters catalyzed by a chiral rhodium catalyst has been realized. A variety of optically pure 1,2,3-trisubstituted cyclopropanes was synthesized in 48-89% yields, with up to 99% ee, and with dr >20:1. Furthermore, research shows that a weak coordination between the chiral rhodium catalyst and ß,γ-unsaturated ketoesters was responsible for the high diastereoselectivity and enantioselectivity of the corresponding products.