Synthetic studies directed toward the phorboxazoles: preparation of the C3–C15 bisoxane segment and two stereoisomers

Authors

Patrick Bernard Greer, Marquette University
William Donaldson, Marquette UniversityFollow

Document Type

Article

Publication Date

7-2002

Publisher

Elsevier

Source Publication

Tetrahedron

Source ISSN

0040-4020

Abstract

A synthetic approach to the C3–C15 segment of the cytotoxic marine metabolite phorboxazoles is described. This segment consists of a methylene linked bisoxane structure. The first pyran ring was constructed by a Lewis acid catalyzed diene–aldehyde cyclocondensation. The β-C-glucoside substitution pattern of this ring was established by a stereoselective allylation. Ozonolysis of vinyl group and enantioselective allylation of the racemic aldehyde generated two separable homoallylic alcohols (−)-22 and (+)-23. The Mosher's esters of each alcohol were determined to be >90% de. Reaction of (−)-22 with acryloyl chloride, followed by ring closing metathesis gave the dihydro-2-pyrone target (−)-5. Mitsunobu inversion of (+)-23 with p-nitrobenzoic acid, hydrolysis, and esterification with acryloyl chloride and ring closing metathesis gave pseudoenantiomeric segment (+)-6.

Comments

Accepted version. Tetrahedron, Vol. 58, Issue 30 (2002), pp 6009-6018. DOI: 10.1016/S0040-4020(02)00613-0. © 2002 Elsevier. Used with permission.

Recommended Citation

Greer, Patrick Bernard and Donaldson, William, "Synthetic studies directed toward the phorboxazoles: preparation of the C3–C15 bisoxane segment and two stereoisomers" (2002). Chemistry Faculty Research and Publications. 67.
https://epublications.marquette.edu/chem_fac/67