Remote Hydroxylation of Methyl Groups by Regioselective Cyclopalladation. Partial Synthesis of Hyptatic Acid-A

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• 作者：André ; s Garc&iacute ; a-Granados ; Pilar E. Ló ; pez ; Enrique Melguizo ; André ; s Parra ; Yolanda Simeó
• 刊名：Journal of Organic Chemistry
• 出版年：2007
• 出版时间：April 27, 2007
• 年：2007
• 卷：72
• 期：9
• 页码：3500 - 3509
• 全文大小：251K
• 年卷期：v.72,no.9(April 27, 2007)
• ISSN：1520-6904

文摘

Hyptatic acid-A (32), a 2,3,24-trihydroxyolean-12-en-28-oic acid, previously isolated from Hyptiscapitata, was obtained from maslinic acid (2). The regioselective cyclopalladation of the axial methylgroup on C-4 of maslinic acid afforded the C-24 hydroxymethylene group due to the presence of aC-2-OR substituent. Nevertheless, hederagenin (7) (23-hydroxy derivative) was formed when thisoxygenated group was not present.