Title: Enantioselective Michael Addition of 4‐Hydroxycoumarins to β,γ‐Unsaturated α‐Oxophosphonates Catalysed by a Bifunctional Squaramide Bearing a Structurally Rigid 9,10‐Ethylene‐9,10‐dihydroanthracene Skeleton
Abstract: Abstract A bifunctional squaramide based on ( R , R )‐11,12‐diamino‐9,10‐ethylene‐9,10‐dihydroanthracene has been developed, and it has demonstrated great advantages over previously reported organocatalysts in the asymmetric Michael addition of 4‐hydroxycoumarins to β,γ‐unsaturated α‐oxophosphonates. Upon quenching the generated β‐4‐hydroxy‐2‐oxo‐2 H ‐chromen‐3‐yl‐substituted acylphosphonate intermediates with DBU and an alcohol or amine as a second nucleophile, the corresponding β‐substituted carboxylates or amides were obtained in acceptable to excellent yields and with high levels of enantioselectivity (80–97 % ee ) in a one‐pot fashion.
Publication Year: 2013
Publication Date: 2013-02-21
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 18
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