Efficient Access to Trifluoromethyl Diarylpyrrolines and their N-Oxides through Enantioselective Conjugate Addition of Nitromethane to β,β-Disubstituted Enones

Cascade reaction for the construction of CF3 containing tetrasubstituted furan ring

Activated olefins are well known nucleophiles, but proton abstraction from the substituted α-methyl group in nitroolefin is rare.

The design of a spiro-pyrrolidine organocatalyst and its application to catalytic asymmetric Michael addition for the construction of all-carbon quaternary centers

A novel chiral spiro-pyrrolidine silyl ether organocatalyst has been designed. Its catalytic asymmetric effect is demonstrated by the Michael addition reaction, which affords the desired products with an all-carbon quaternary center in up to 99% ee and 87% yield. Furthermore, the reaction process has been investigated via in situ NMR experiments.

A general, scalable, organocatalytic nitro-Michael addition to enones: enantioselective access to all-carbon quaternary stereocenters

A tert-leucine-derived chiral diamine catalyzes the asymmetric Michael addition of nitromethane to five-, six-, and seven-membered β-substituted cyclic enones with excellent enantioselectivity, offering scalable, asymmetric access to all-carbon quaternary stereocenters. The reaction scope can be expanded to include linear acyclic enones, and excellent levels of enantioselectivity are also observed. Furthermore, this organocatalytic, asymmetric nitro-Michael reaction is amenable to multigram scale-up and applications in the construction of an eudesmane sesquiterpenoid skeleton.

Asymmetric vinylogous Michael reaction of cyclic enones with silyloxy furans

A chiral, primary diamine catalyzed enantioselective vinylogous Michael reaction of cyclohexenone/medium and large cyclic enones with various 2-silyloxyfuran has been explored.

A multicomponent Ni-, Zr-, and Cu-catalyzed strategy for enantioselective synthesis of alkenyl-substituted quaternary carbons

The availability of enantiomerically enriched carbonyl-containing compounds is essential to the synthesis of biologically active molecules. Since catalytic enantioselective conjugate addition (ECA) reactions directly generate the latter valuable class of molecules, the design and development of such protocols represents a compelling objective in modern chemistry. Herein, we disclose the first solution to the problem of ECA of alkenyl groups to acyclic trisubstituted enones, an advance achieved by adopting an easily modifiable and fully catalytic approach. The requisite alkenylaluminum reagents are synthesized with exceptional site- and/or stereoselectivity by a Ni-catalyzed hydroalumination process, and the necessary enones are prepared through a site- and stereoselective zirconocene-catalyzed carboalumination/acylation reaction. The all-catalytic procedure is complete within four hours, furnishing the desired products in up to 77 % overall yield and 99:1 enantiomeric ratio.

Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

Starting from easily accessible gem-difluoropropargylic derivatives, a DBU-mediated isomerisation affords enones in fair yields with a gem-difluoroalkyl chain. These derivatives were used to prepare pyrazolines and pyrrolines with the desired gem-difluoroalkyl side chain by cyclocondensations in good yields and with excellent stereoselectivity. A one-pot process was also successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated.