An enantioselective approach to (+)-laurencin

A convergent enantioselective route to an advanced intermediate for the synthesis of the marine natural product (+)-laurencin has been developed. The methodology employs ring-opening of an ephedrine-based spiro-epoxide with a chiral secondary alcohol, hemiacetal allylation and ring closing metathesis as the key steps for elaboration of the functionalized medium-ring ether moiety in laurencin.