Organocatalytic asymmetric synthesis of benzothiazolopyrimidines via a [4 + 2] cycloaddition of azlactones with 2-benzothiazolimines. Issue 20 (18th August 2021)

• Record Type: Journal Article
• Authors: Ke, Chaoqi; Liu, Zhenzhong; Ruan, Sai; Feng, Xiaoming; Liu, Xiaohua
• Is Part Of: Organic chemistry frontiers. Volume 8:Issue 20(2021)
• Page Start: 5705
• Page End: 5709
• Publication Date: 2021-08-18
• Subjects: Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1039/d1qo00948f
• Languages: English
• ISSNs: 2052-4110

Abstract

Abstract : A chiral guanidine-catalyzed [4 + 2] cycloaddition of 2-benzothiazolimines with azlactones characterized by a high yield, ee, and dr and a broad substrate scope has been developed. Gram-scale synthesis and derivatization of the product revealed the potential of utility. Abstract : An easily available L-proline-derived guanidine-amide was found to be efficient at catalyzing a [4 + 2] cycloaddition of azlactones with 2-benzothiazolimines, affording various benzothiazolopyrimidines bearing adjacent tertiary and quaternary stereogenic centers in excellent yields at 2 mol% loading. The diastereoisomers of the main adducts differed from those in a previous bifunctional organocatalytic system.