120016-58-2Relevant articles and documents
Synthetic study of kosinostatin aglycone: Synthesis of BCDE rings using alkoxycarbonylmethylation of diazonaphthoquinone
Kitamura, Mitsuru,Kubo, Kenji,Yoshinaga, Shogo,Matsuzaki, Hiroki,Ezaki, Kantaro,Matsuura, Taisuke,Matsuura, Daigo,Fukuzumi, Noriyuki,Araki, Keiichiro,Narasaki, Masafumi
, p. 1653 - 1656 (2014/03/21)
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.
