Construction of Chiral Isotetronic Acid-Fused Thiochromane via Doubly Annulative Strategy
Yiran Mo, Xuehuan Zhang, Yongqi Yao, Cong Duan, Ling Ye, Zhichuan Shi, Zhigang Zhao, Xuefeng Li
Abstract
A sulfa-Michael/aldol/lactonization cascade reaction has been established to construct isotetronic acid-fused thiochromanes in a highly stereoselective fashion (≥11:1 dr, 35-98% ee). The tricyclic products were obtained in 35-99% isolated yields in the presence of a bifunctional squaramide. Three reactive sites of β,γ-unsaturated α-ketoester, including the less-explored ester carbonyl group, were sequentially utilized to construct two fused heterocycles in a one-pot operation.
Topics & Concepts
ChemistryStereochemistryCombinatorial chemistrySulfur-Based Synthesis TechniquesSynthesis and Catalytic ReactionsAxial and Atropisomeric Chirality Synthesis