Chiral Squaramide Catalyzed Asymmetric Spiroketalization toward Aromatic [6,5] Spiroketals
Tarun Kumar Roy, Sachin S. Gorad, Prasanta Ghorai
Abstract
Herein is disclosed an efficient enantio- and diastereoselective spiroketalization of aromatic ketone tethered to ortho-homoformyl and enone moiety via in situ enol formation using quinine derived squaramide organocatalyst to access aromatic [6,5] spiroketals with complete atom economy. Furthermore, aromatic spiroketals undergo Brønsted acid catalyzed Piancatelli type rearrangement to provide dihydronaphtho[1,2-b]furans with retention of the enantioselectivities.
Topics & Concepts
SquaramideChemistryMoietyEnolAromaticityCatalysisKetoneEnantioselective synthesisStereochemistryOrganic chemistryOrganocatalysisMoleculeSynthesis of Indole DerivativesAxial and Atropisomeric Chirality SynthesisChemical Synthesis and Reactions