Control of the Organocatalytic Enantioselective α-Alkylation of Vinylogous Carbonyl Enolates for the Synthesis of Tetrahydropyran Derivatives and Beyond
Pavan Sudheer Akula, Yung-Ju Wang, Bor‐Cherng Hong, Gene‐Hsiang Lee, Su‐Ying Chien
Abstract
The organocatalytic α-alkylation of vinylogous carbonyl compounds to hydroxynitroolefins for the synthesis of hemiacetals was realized with excellent enantioselectivities and in high yields. High diastereoselectivity (up to >20:1) has been accomplished with the addition of Et3N. The α- and γ-alkylation of vinylogous ketone against nitroolefins displayed high but opposite facial selectivities. Transformation of the hemiacetal products to other polycyclic compounds, including the euroticin B analog, has been demonstrated.
Topics & Concepts
ChemistryTetrahydropyranAlkylationEnantioselective synthesisKetoneHemiacetalOrganic chemistryCatalysisRing (chemistry)Chemical synthesis and alkaloidsMarine Sponges and Natural ProductsSynthetic Organic Chemistry Methods