Total Syntheses of 11‐Acetoxy‐4‐deoxyasbestinin D, 4‐Deoxyasbestinin C, Asbestinin‐10, ‐20, ‐21 and ‐23

Abstract

Six members of the asbestinin family of marine diterpenen atural productsh ave been synthesized in an efficient and stereoselective manner from as ingle oxa-bridged intermediate. Five of these natural products have not been synthesized previously and the structures of four of them have been confirmed as those proposed originally or following revisions to the original structures. The fifth natural product-asbestinin-21-has been shown to be ad iastereomer of the compoundthat had been proposed previously.

Marine natural products

“…Stereoselective syntheses of 11-acetoxy-4deoxyasbestinin D, 4-deoxyasbestinin C and asbestinins -10, -20, -21 and -23 have been reported. 581 Waixenicin A, a xenicane diterpenoid originally isolated from Sarcothelia edmondsoni, demonstrates several pharmacological activities including neurite outgrowth and reduction of hypoxic-ischemic brain injury, all of which have been recently reviewed. 582 The structures and biological activities observed for over 200 sterols isolated from cnidarians has also been reviewed.…”

The Discreet Structural Diversity of Briarellins: DU8+ Guided Multiple Structure Revisions Yielded Two Unknown Structural Types

“…For example, Rodríguez reassigned the structures of asbestinin-10, asbestinin-20, and asbestinin-21 in a revision, which involved ‘relocation’ of the substituents from C4 to C6, while not requiring changes to their core framework . The Clark group recently published total synthesis of several asbestinins, confirming these prior revisions and further correcting the C-7 stereoconfiguration in asbestinin-21. As the difference between the two C-7 epimers is subtle, we used this opportunity to test whether DU8+ could differentiate between these two epimers of asbestinin-21.…”