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The fully substituted C17-C30 bis-tetrahydrofuran fragment of the proposed structure of iriomoteolide-13a has been assembled via asymmetric dihydroxylation-S(N)2 cyclization of 19-mesyloxy-21ene-26-yne and PdCl2-catalyzed syn-oxypalladation of 26-ene17,21,23,28-tetraol as the key steps. The syn-oxypalladation process gave an 89:11 diastereoselectivity and tolerated the free poly-hydroxy groups in the highly functionalized substrate.

Synthesis of the C19-truncated maltepolide E has been accomplished via a diene-ene ring-closing metathesis (RCM) strategy without damage to the C11-C14 alkenyl epoxy unit. Upon release of the C17-OH group, it attacked at the C14 position with double bond migration and epoxide ring opening to furnish the C19-truncated maltepolides A and B as proposed for the biosynthesis of maltepolides.

Synthesis of the C19-truncated maltepolide E has been accomplished via a diene–ene RCM strategy without damage to the C11–C14 alkenyl epoxy unit. Upon release of the C17-OH group, it attacked at the C14 position with double bond migration and epoxide ring-opening to furnish the C19-truncated maltepolide A and B as proposed for the biosynthesis of maltepolides. Preliminary cytotoxicity data of the synthesized C19-truncated maltepolides against L929 mouse fibroblast cell line suggest irrelevance of the vinyl epoxide and importance of the conjugated dienyl keto unit for the observed anticancer activity.