Merging Chiral Brønsted Acid/Base Catalysis: An Enantioselective [4 + 2] Cycloaddition of o-Hydroxystyrenes with Azlactones.
J Org Chem
; 81(4): 1681-8, 2016 Feb 19.
Article
em En
| MEDLINE
| ID: mdl-26800116
ABSTRACT
An enantioselective [4 + 2] cycloaddition of o-hydroxylstyrenes with azlactones has been established by merging chiral Brønsted acid (chiral phosphoric acid) and base (chiral guanidine) catalysis, which constructed a biologically important dihydrocoumarin scaffold in an efficient and enantioselective style (up to 99% yield, 964 er). This approach has not only realized the successful application of o-hydroxylstyrenes as oxa-diene precursors in catalytic asymmetric cycloadditions but also established a new cooperative catalytic system of chiral phosphoric acid and chiral guanidine.
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MEDLINE
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En
Ano de publicação:
2016
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Article