1 Laboratory of Organic Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Barcelona-08028, Spain. amat@ub.edu joanbosch@ub.edu.
A short enantioselective synthesis of the macrocyclic core 19 of callyspongiolide, involving a homocrotylboration of aldehyde 4, a Still-Genari olefination, an esterification with alcohol 17, and a ring-closing metathesis, is reported.