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Solid-phase Synthesis of [4.4] Spirocyclic Oximes
Published on: February 6, 2019
Asymmetric [4 + 2] cycloaddition synthesis of 4H-chromene derivatives facilitated by group-assisted-purification
Hossein Rouh1, Yao Tang1, Sai Zhang1
1Department of Chemistry and Biochemistry, Texas Tech University Lubbock Texas 79409-1061 USA guigen.li@ttu.edu.
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.
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