Rhodium-Catalyzed Stereoselective Intramolecular [5 + 2] Cycloaddition of 3‑Acyloxy 1,4-Enyne and Alkene

The
first rhodium-catalyzed intramolecular [5 + 2] cycloaddition
of 3-acyloxy 1,4-enyne and alkene was developed. The cycloaddition
is highly diastereoselective in most cases. Various cis-fused bicyclo[5.3.0]­decadienes were prepared stereoselectively.
The chirality in the propargylic ester starting materials could be
transferred to the bicyclic products with high efficiency. Electron-deficient
phosphine ligand greatly facilitated the cycloaddition. Up to three
new stereogenic centers could be generated. The resulting diene in
the products could be hydrolyzed to enones, which allowed the introduction
of more functional groups to the seven-membered ring.