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

Abstract 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.