Phosphine-mediated one-pot reactions: Syntheses of β-acylated alkylidene indandiones and furo[2,3-f]dibenzotropones via MBH-type annulation/acylation or Wittig reaction

Phosphine-mediated one-pot reactions have been developed that involve two mechanistically distinct reactions assembled in one reaction vessel via the sequential addition process. The first step involves MBH-type annulation of α,β-ynones to afford cyclic products in each case, which then engages in subsequent β-acylation or intramolecular Wittig reactions. The reaction conditions are mild and efficient, providing acylated alkylidene indandiones in 70%–99% yields or furo[2,3-f]dibenzotropones in 65%–91% yields, respectively.