- A convergent total synthesis of phorboxazole A
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The potent cytostatic marine metabolite phorboxazole A (see structure) was prepared from three key fragments. Following attachment of a major portion of the side chain through C32-C33 and an intermolecular E-selective olefination reaction to form the C19-
- Gonzalez, Miguel A.,Pattenden, Gerald
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p. 1255 - 1258
(2007/10/03)
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- Total synthesis of (+)-phorboxazole A, a potent cytostatic agent from the sponge Phorbas sp.
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A convergent total synthesis of phorboxazole A (1a), from the C(3-19), C(20-27) and C(33-46) fragments 5, 4 and 91, respectively, concentrating on stereocontrolled formation of the bonds at C(2-3), C(19-20) and C(27-28), is described. Although a coupling reaction between a macrolide ketone and the side chain substituted sulfone, at C(27-28) was not successful, a Wadsworth-Emmons olefination involving the oxane methyl ketone 4 and an oxazole produced the oxane 90 which was next coupled to 91 leading to the C(20-46) unit 100. A further coupling of 100 to 71c at C(19-20) then led to 105, ultimately, and the synthesis was completed by a macrocyclisation reaction from 105, at the C(2-3) alkene bond, followed by deprotection of 106.
- Pattenden, Gerald,Gonzalez, Miguel A,Little, Paul B,Millan, David S,Plowright, Alleyn T,Tornos, James A,Ye, Tao
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p. 4173 - 4208
(2007/10/03)
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