Carvone-Derived P‑Stereogenic Phosphines: Design, Synthesis, and Use in Allene–Imine [3 + 2] Annulation

We
have prepared a previously unreported family of P-stereogenic
[2.2.1] bicyclic chiral phosphines through straightforward syntheses
starting from the natural product carvone. This design rationale prompted
the development of an unforeseen C-dealkenylation reaction. We have
applied these organocatalysts in the asymmetric syntheses of a bevy
of pyrrolines, obtained in high yields and enantioselectivities, including
a biologically active small molecule, efsevin.