Highly Chemoselective Synthesis of Purino[3,2-<i>c</i>]oxazoles via the Asymmetric Dearomative [3+2] Cycloaddition of Purines with Donor–Acceptor Oxiranes
Mengcheng Zhang, Dong‐Chao Wang, Hai‐Ting Wang, Gui‐Rong Qu, Hai‐Ming Guo
Abstract
A Ni(II)/bisoxazoline-catalyzed asymmetric dearomative [3+2] cycloaddition of substituted purines with donor–acceptor oxiranes was developed. This reaction, which proceeds via highly chemoselective C–C bond cleavage of the oxiranes, accesses chiral purino[3,2-c]oxazole compounds (≤99% ee after enrichment via crystallization). The electronic effects of the purine ring determine the reactivity of the substrate. The general applicability of this method was illustrated by gram-scale synthesis, the diverse transformations of the product, and the promising biological activities of selected derivatives.
Topics & Concepts
ChemistryCycloadditionPurine metabolismCombinatorial chemistryOxazoleRing (chemistry)PurineStereochemistryAcceptorCleavage (geology)Reactivity (psychology)RacemizationBond cleavageOrganic chemistryCatalysisEnzymeGeotechnical engineeringPathologyEngineeringFracture (geology)Condensed matter physicsAlternative medicineMedicinePhysicsCatalytic C–H Functionalization MethodsSynthesis and Catalytic ReactionsCyclopropane Reaction Mechanisms