A facile approach to the total synthesis of both enantiomers of the 14‐membered macrolactone aspergillide C is described. The strategy employed was also utilized for the synthesis of C4‐epimers of both the enantiomers of aspergillide C. The key reactions include Sharpless kinetic resolution, Achmatowicz reaction, Ferrier type alkynylation, hydrosilylation‐protodesilylation, Corey–Bakshi–Shibata (CBS) mediated reduction, and Yamaguchi macrolactonization.

The stereoselective total syntheses of (+)-aspergillide B and (+)-7-epi-aspergillide A were achieved. The key reactions include Noyori's asymmetric transfer hydrogenation, an Achmatowicz rearrangement, a Ferrier-type alkynylation, a 578 hydrosilylation-protodesilylation, a CBS (Corey-Bakshi-Shibata) oxazaborolidine reduction, a Yamaguchi macrolactonization, and a Mitsunobu macrolactonization.Scheme 2. Synthesis of acetate 7 (LDA = lithium diisopropylamide).

The stereoselective protective group-free synthesis of the C1-C16 fragment of (+)-sorangicin A consisting of a dihydropyran subunit with a chiral alkyl substituent is achieved. The synthesis of the 4-stereogenic centered subunit involved key reactions such as Noyori asymmetric transfer hydrogenation, Achmatowicz oxidative rearrangement, and highly diastereoselective allylation of the Achmatowicz adduct.

A flexible stereoselective approach to the common C1-C14 skeleton present in natural products of the pseudomonic acid family is described. The strategy has been extended and the total synthesis of pseudomonic acid methyl monate C was achieved. The key synthetic reactions utilized include Achmatowicz rearrangement, Johnson-Claisen rearrangement, Julia-Kocienski olefination, and Horner-Wadsworth-Emmons olefination reaction.

SummaryAn enantioselective formal total synthesis of aspergillide C is accomplished using commercially available tri-O-acetyl-D-galactal employing a Ferrier-type C-glycosylation, utilizing a Trost hydrosilylation and protodesilylation as key reactions.

Scheme 4. Proposed cross-ring cleavage mechanisms for (a) isomer 3 and (b) isomer 4.

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