An efficient protocol for the highly regioselective opening of aliphatic zirconacyclopentadienes is reported. The one-pot process involves a zirconocene-mediated cyclization of 1,6-diynes and highly selective cleavage of the metallacycles with NBS and enables a concise synthesis of the tetrahydrofuran-core of the leupyrrins.
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Regioselective 1,4-Addition of P(O)-H Species to In SituFormed 1-Benzopyrylium Ion from C3-Substituted 2-Chromene Hemiketals to Construct C3-Functionalized C4-Phosphorylated 4-Chromenes.
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