کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5270726 | 1385423 | 2014 | 4 صفحه PDF | دانلود رایگان |
A synthetic study of kosinostatin aglycone is reported. Synthesis of key intermediate lactone 3, which corresponds to the BCDE ring fragment, was accomplished, and the precursor BCD ring fragment 5 was synthesized via two routes. First, 5 was synthesized from 2,5-dimethoxybenzaldehyde 16 by the combination of typical known transformations including efficient application of non-aqueous OsO4 oxidation in the presence of PhB(OH)2. However the synthesis required 15 long steps, and its main difficulty was ortho-alkoxycarbonylmethylation of 1-naphthol. Next we attempted to apply our recently developed alkoxycarbonylmethylation of diazonaphthoquinone for the synthesis of 5, and 5 was successfully synthesized in 9 steps from the same starting compound 16. Finally, 5 was stereoselectively converted to lactone 3 via trifluoroacetic acid-mediated cyclization of the 3,4-epoxycylohexanecarboxylic acid derivative.
Journal: Tetrahedron Letters - Volume 55, Issue 9, 26 February 2014, Pages 1653-1656