Total Synthesis of Cyanolide A in the Absence of Protecting Groups, Chiral Auxiliaries, or Premetalated Carbon Nucleophiles

No protection, no problem: The C2-symmetric macrodiolide cyanolide A is prepared in six steps from neopentyl glycol and allyl acetate by iridium-catalyzed double asymmetric allylation and a tandem cross-metathesis/oxa-Michael cyclization to form the substituted pyran. The synthesis is accomplished in the absence of any protecting groups, chiral auxiliaries, or premetalated carbon nucleophiles in fewer than half the steps of any prior approach.