Asymmetric [4 + 2] cycloaddition synthesis of 4H-chromene derivatives facilitated by group-assisted-purification (GAP) chemistry.

ABSTRACT: In this work, we present a strategy for the preparation of functionalized 4H-chromene derivatives via a Cs₂CO₃-catalyzed [4 + 2] cycloaddition of enantiopure chiral salicyl N-phosphonyl imines with allenoates. Fifteen examples were achieved in excellent yields and diastereoselectivity. The products were purified simply by washing the crude mixture with hexanes following the Group-Assisted Purification (GAP) chemistry/technology to bypass traditional separation methods. The absolute configuration was unambiguously determined by X-ray structure analysis.

SUBMITTER: Rouh H 

PROVIDER: S-EPMC9044656 | biostudies-literature | 2021 Dec

REPOSITORIES: biostudies-literature