Ir-Catalyzed Asymmetric Cascade Allylation/Spiroketalization Reaction for Stereoselective Synthesis of Oxazoline-Spiroketals
Hui Yan, Xusheng Shao, Xiaoyong Xu, Zhong Li, Wu‐Lin Yang
Abstract
An asymmetric cascade allylation/spiroketalization reaction between 2-(1-hydroxyallyl)phenols and 5-methyleneoxazolines is accomplished by using a chiral Ir(I) catalyst derived from commercially available iridium precursor and the Carreira ligand. This protocol furnishes a class of structurally novel and unique oxazoline-spiroketals in up to 86% yield, >99% ee and >20:1 dr. Moreover, control experiments reveal that 4,4-disubstitution on 5-methyleneoxazolines is necessary to avoid the aromatization and for the spiroketalization to occur. On the basis of this, a plausible reaction mechanism is illustrated.
Topics & Concepts
ChemistryOxazolineStereoselectivityCatalysisIridiumYield (engineering)Combinatorial chemistryCascadeLigand (biochemistry)Enantioselective synthesisAromatizationCascade reactionStereochemistryOrganic chemistryReceptorBiochemistryMetallurgyChromatographyMaterials scienceSynthesis of Indole DerivativesOxidative Organic Chemistry ReactionsAxial and Atropisomeric Chirality Synthesis