2007

AlkaloidsU 0600 Annulation of β-Aryl-α-nitro-α,β-enals and 2,2-Dimethyl-1,3-dioxan-5-one:

A One-Step Assembly of Nitrocyclitols. Application to a Short Practical Synthesis of (±)-7-Deoxy-2-epi-pancratistatin Tetraacetate. — A novel, highly stereocon-trolled formal [3 + 3] annulation of α-nitro-enals (IV) with the enamine derived from ketone (V) and pyrrolidine affords protected nitrocyclitols (VI) with five newly created stereocenters. This approach is used as the key step in a short, multi-gram synthesis of pancratistatin analogue (XI). — (ORTIZ, J. C.; OZORES, L.; CAGIDE-FAGIN, F.; ALONSO*, R.; Chem. Commun. (Cambridge) 2006, 40, 4239-4241; Dep. Quim. Org., Fac. Quim., Univ. Santiago de Compostela, E-15782 Santiago de Compostela, Spain; Eng.) — M. Paetzel

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