Self-Sensitized Diastereodifferentiating<b><i>Z</i></b>-<b><i>E</i></b>Photoisomerization of 3-, 4-, and 5-Benzoyloxycyclooctenes: Intra- versus Intermolecular Photosensitization
作者:Yoshihisa Inoue、Keisuke Matsuyama、Toru Inoue
DOI:10.1055/s-2001-15062
日期:——
diastereomeric excesses (de’s) of up to 43%. The major diastereomer produced from 1Z was switched from (1R*,3R*)-1E (26% de) to (1R*,3S*)-1E (– 11% de) by simply increasing the substrate concentration from 1 mM to 50 mM. This unusual switching of product chirality is attributed to the opposite diastereoselectivities for intraand intermolecular photosensitization. In contrast, 2Z and 3Z did not show
Synthesis 2001, No. 8, 18 06 2001。文章标识符:1437-210X,E;2001,0,08,1167,1174,ftx,en;C01401SS.pdf。© Georg Thieme Verlag Stuttgart · 纽约 ISSN 0039-7881 摘要:在 254 nm 照射下,(Z)-3-、4- 和 5-苯甲酰氧基环辛烯 (1Z–3Z) 通过对相应分子内和/或分子间的致敏作用有效地异构化非对映异构体 E 异构体 (1E–3E) 具有低至中度非对映异构体过量 (de's) 高达 43%。通过简单地将底物浓度从 1 mM 提高到 50毫米。这种产物手性的不寻常转换归因于分子内和分子间光敏化的相反的非对映选择性。相比之下,2Z 和 3Z 没有表现出这样的切换行为,但在很宽的底物浓度(0.04-50 mM)范围内,始终给出高达 9% 和 43% de 的单