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

In this work, we present a strategy for the preparation of functionalized 4 H -chromene derivatives via a Cs 2 CO 3 -catalyzed [4 + 2] cycloaddition of enantiopure chiral salicyl N -phosphonyl imines with allenoates. Fifteen examples were achieved in excellent yields and diastereoselectivity. The pr...

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Bibliographic Details
Published in:	RSC advances Vol. 11; no. 63; pp. 3979 - 39796
Main Authors:	Rouh, Hossein, Tang, Yao, Zhang, Sai, Ali, Ahmed I. M, Surowiec, Kazimierz, Unruh, Daniel, Li, Guigen
Format:	Journal Article
Published:	14-12-2021
Online Access:	Get full text
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Summary:	In this work, we present a strategy for the preparation of functionalized 4 H -chromene derivatives via a Cs 2 CO 3 -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. A new asymmetric method for the synthesis of highly functionalized 4 H -chromenes was developed via Group-Assisted Purification (GAP) chemistry and shown in good to high yield and excellent diastereoselectivity.
Bibliography:	Electronic supplementary information (ESI) available. CCDC 2114683 For ESI and crystallographic data in CIF or other electronic format see DOI 10.1039/d1ra08323f
ISSN:	2046-2069
DOI:	10.1039/d1ra08323f