Chiral Oxazaborolidine−Aluminum Bromide Complexes Are Unusually Powerful and Effective Catalysts for Enantioselective Diels−Alder Reactions
作者:Duan Liu、Eda Canales、E. J. Corey
DOI:10.1021/ja068637r
日期:2007.2.1
acid catalyst than protonated 1 (i.e., 2) for enantioselectiveDiels−Alderreactions. Only 4 mol % of catalyst 3 is required to achieve yields and enantiomeric purities of 90% over a broad range of achiraldienes and dienophiles. The ligand from which 3 is derived can be recovered easily and with high efficiency. The method is illustrated by 22 examples.
Catalytic enantioselective Diels–Alder reactions of furans and 1,1,1-trifluoroethyl acrylate
作者:Do Hyun Ryu、Kyung Hwa Kim、Jae Yi Sim、E.J. Corey
DOI:10.1016/j.tetlet.2007.06.097
日期:2007.8
CatalyticenantioselectiveDiels–Alderreactions of furans and 1,1,1-trifluoroethyl acrylate in the presence of oxazaborolidium catalysts 2 or 3 provide 7-oxabicyclo[2.2.1]hept-5-enes with high endo-selectivity and excellent enantioselectivity.
Cationic Chiral Fluorinated Oxazaborolidines. More Potent, Second-Generation Catalysts for Highly Enantioselective Cycloaddition Reactions
作者:Karla Mahender Reddy、Eswar Bhimireddy、Barla Thirupathi、Simon Breitler、Shunming Yu、E. J. Corey
DOI:10.1021/jacs.6b00100
日期:2016.2.24
placement of fluorine substituents in the chiral ligand. This approach has led to a new, second-generation family of chiral oxazaborolidinium cationic species which can be used to effect many Diels-Alder reactions in >95% yield and >95% ee usingcatalyst loadings at the 1-2 mol % level. The easy recovery of the chiral ligand makes the application of these new catalysts especially attractive for large-scale
Asymmetric synthesis of (+)-cis-nemorensic acid from a chiral Diels–Alder adduct of 2,5-dimethylfuran
作者:Jae Yi Sim、Geum-Sook Hwang、Kyung Hwa Kim、Eun Mi Ko、Do Hyun Ryu
DOI:10.1039/b710537a
日期:——
(+)-cis-Nemorensic acid (1) was synthesized from a chiral DielsâAlder adduct (4) prepared by a catalytic enantioselective DielsâAlder reaction with 2,5-dimethylfuran and 2,2,2-trifluoroethyl acrylate.