[2 + 4] Annulation of Alkyl(phenyl)phosphinic Chlorides with Enones: Stereoselective Synthesis of δ‑Phosphinolactones

Various δ-phosphinolactones
(δ-phostines) are efficiently
and diastereospecifically synthesized in good to excellent yields
from direct [2 + 4] annulation of alkyl(phenyl)phosphinic chlorides
and α,β-enones in the presence of LiHMDS. The annulation
involves deprotonation, Michael addition, and nucleophilic substitution
and features readily available materials, good to excellent yields,
diastereospecificity, atom and step economy, wide substrate scope,
easy separation, and mild conditions.