Detection and the analysis of the factors affecting the competition between ring closure, internal rotation, and cleavage in diradical intermediates formed in allene cycloaddition reactions
Diels-Alder reactions using supercritical water as an aqueous solvent medium
作者:Michael B. Korzenski、Joseph W. Kolis
DOI:10.1016/s0040-4039(97)01274-4
日期:1997.8
A variety of Diels-Alderreactions have been performed in supercritical water as a reaction medium. The rapid reaction of Diels-Alderreactions of cyclopentadiene and various electron poor dienophiles such as diethyl fumarate and acrylonitrile is observed in supercritical water, and leads to high yields of clean products without added catalysts.
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
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.
Detection and the analysis of the factors affecting the competition between ring closure, internal rotation, and cleavage in diradical intermediates formed in allene cycloaddition reactions