Regio- and Diastereoselective [3 + 2]-Spiroannulation of Benzoxazines with Chalcones: A Rh(III)-Catalyzed Redox-Neutral Approach to α-Aroyl Spiro-Indanamines
Writhabrata Sarkar, Koushik Naskar, Shantonu Roy, Imtiaj Mondal, Sudip Karmakar, Aniket Mishra, Indubhusan Deb
Abstract
We report an atom-economic Rh(III)-catalyzed [3 + 2]-spiroannulation reaction between cyclic ketimines and α,β-unsaturated carbonyl compounds, allowing the synthesis of novel spirocycles with concomitant generation of three stereogenic centers in one pot. The reaction does not require any silver additives or external oxidants and is believed to proceed in a redox-neutral manner. A broad substrate scope with good functional group tolerance permitted the synthesis of a vast spectrum of spirocyclic 1,4-benzoxazine derivatives containing polysubstituted α-aroyl-indanamines in good to excellent yields with high diastereoselectivity.
Topics & Concepts
ChemistryStereocenterRedoxCatalysisCombinatorial chemistrySubstrate (aquarium)Reaction conditionsEnantioselective synthesisOrganic chemistryOceanographyGeologyCatalytic C–H Functionalization MethodsCyclopropane Reaction MechanismsCatalytic Cross-Coupling Reactions