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Updated: Jun 28, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Asymmetric 1,3-dipolar cycloaddition with a P-stereogenic dipolarophile: an efficient approach to novel P-stereogenic
Nikolai Vinokurov1, K Michał Pietrusiewicz, Sławomir Frynas
1Institut für Organische Chemie, Leibniz Universität Hannover, Schneiderberg 1B, Hannover, Germany.
Abstract:
The asymmetric 1,3-dipolar cycloaddition of the P-stereogenic dipolarophile (S(p),S(p))-6 to C,N-diphenylnitrone (7) led to previously unknown P-stereogenic isoxazolinyl diphosphine dioxides (R(p),S(p))-8 in enantio- and diastereomerically pure form; their stereospecific reduction with Ti(OiPr)(4)/PMHS proceeds in high yield with retention of configuration at the phosphorus atoms to give enantio- and diastereomerically pure diphosphines, which are conveniently purified via the corresponding diphosphine-diboranes.
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