Enantioselective total synthesis of the proposed structure of macrolide iriomoteolide-1b

An enantioselective total synthesis of the proposed structure of macrolide iriomoteolide-1b has been achieved by a convergent protocol, which was featured by an enantioselective organocatalytic transfer hydrogenation of enal, a Julia-Kocienski olefination to establish the C15-C16 E-olefin moiety, a Kulinkovich reaction associated with cyclopropyl-allyl rearrangement to produce allyl stannane and ytterbium triflate and carboxylic acid promoted allylation between allyl stannane and aldehyde with tertiary alcohol at the α-position. The construction of macrolide 2 was realized by the successful implementation of RCM utilizing 5 mol % Grubbs's second generation catalyst at room temperature with E-isomer as a single product.