Enantiospecific synthesis of the the tricyclxc nucleus of acetoxycrenulide by claisen ring exfansion

Article abstract of DOI:10.1016/S0040-4039(00)97221-6

The known R lactone 4 has been transformed in 9 steps into optically pure 2, a molecule possessing the ring system characteristic of the crenulide diterpenes. In the key step, chirality transfer is accomplished via a Z-selective Claisen ring expansion.