Asymmetric Synthesis of Hydrophenanthrenones Bearing Multiple Stereogenic Centers via Squaramide-Catalyzed Domino
Manisha Sharma1, Tamanna1, Pankaj Chauhan1
1Department of Chemistry, Indian Institute of Technology Jammu, NH-44, Nagrota Bypass, Jammu, 181221 Jammu and Kashmir, India.
Abstract:
An unprecedented stereoselective route for procuring tetrahydrophenanthren-2(1H)-ones bearing up to five contiguous stereogenic centers has been accomplished. A bifunctional squaramide enables a domino 1,4-/1,4-addition desymmetrization reaction sequence between the newly developed β-nitrostyrene-tethered 2,5-cyclohexadienones and trisubstituted enolizable nucleophiles to provide direct access to the polyfunctionalized hydrophenanthren-2(1H)-ones in excellent enantio- (up to >99%) and diastereoselectivity (up to >20:1). By using a psedoenantiomeric squaramide, the enantiomers of hydrophenanthrene derivatives were also accessed with excellent stereocontrol.
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