Enantioselective Synthesis of Arglabin

Closing the ring: The first enantioselective synthesis of the guanianolide natural product arglabin and its dimethylamino adduct, which shows promising results in the treatment of various tumors, has been achieved. Key steps include a CuI-catalyzed asymmetric cyclopropanation, a stereoselective Sakurai allylation with a retroaldol/lactonization cascade, and a second Sakurai allylation with ring-closing metathesis (RCM).