93 光学活性シザンドリン及びゴミシンAの全合成(ポスター発表の部)

概要

論文の詳細を見る
Optically pure schizandrin (1), gomisin A (2), and isoschizandrin (3) were synthesized in naturally occurring configurations. The synthesis of schizandrin (1) started with optically active half ester (17), which can be obtained easily by the asymmetric hydrogenation of 16. After conversion of 17 to 4 in four steps, 4 was subjected to the iron (III) perchlorate mediated oxidative coupling reaction to give biphenyl (10) in 90% yield. For the stereoselective introduction of hydroxyl group, 10 was converted into single epoxide (20). Then, optically pure schizandrin (1) was obtained by the reductive cleavage of benzylic C-O bond and following deoxygenation. The synthesis of isoschizandrin (3) was achieved from 20 by the use of stereoselective epoxidation of 22 affording 23 as a sole product, which was then transformed into 3 straightforwardly. The synthesis of gomisin A (2) was achieved as follows. The oxidative coupling of 5, which possesses methylenedioxy group, gave two regiochemical isomers (11a, 11b). On the other hand, catechol (6) was found to afford desired isomer (11a) in 62% yield as a sole product after methylenation of catechol group. Then the transformation of 11a to gomisin A (2) was achieved by the stereoselective introduction of hydroxyl group as described above.
1992-09-10