Journal of Organic Chemistry p. 1011 - 1018 (1993)
Update date:2022-07-30
Topics:
Inoue, Yoshihisa
Yamasaki, Noritsugu
Yokoyama, Taizo
Tai, Akira
In an effort to generate photoproducts with higher optical purities (op), two novel strategies, i.e., intra/intermolecular triplex formation and increased steric hindrance, have been employed in the enantiodifferentiating Z -> E photoisomerization of cyclooctene (1) sensitized by optically active (ar)alkyl benzene(poly)carboxylates 2-5 at temperatures ranging from 25 to -90 deg C.The newly synthesized benzenepolycarboxylates, possessing extremely bulky and/or electron-donating (ar)alkyl groups, gave products with the highest op's ever reported for the enantiodifferentiating photosensitizations, not only at low temperatures (up to 64percent op at -89 deg C) but also at ambient temperature (50percent op).Both strategies to fix the sensitizer conformation and to induce more dynamic conformational changes in the exciplex/triplex intermediate are shown to function well and to give very high op's.The temperature-dependence studies also demonstrate that the temperature switching of the product chirality is not an extraordinary but rather a general phenomenon, which is attributed to the significant contribution of the entropy factor in the enantiodifferentiating process, caused by the dynamic structural change in the excited complex.
View MoreSuzhou Jingye Medicine & Chemical Co., Ltd
website:http://www.jingyechem.cn
Contact:+86-512-66658588
Address:No. 88, Sanlian Street, Jinfeng Road, Suzhou New District, Jiangsu Province, P. R. China
Contact:+86-577-65618087-605
Address:Room 402, Unit 4 Xinhu Bldg. Waitan Ruian City, Zhejiang China.
Chongqing KonAo Health Co.,Ltd
Contact:13687578375
Address:wuhan hubei china
WEIFANG RICHEM INTERNATIONAL LTD
Contact:86-536-2222176
Address:weifang,shandong
Linyi Shengxin Pharmaceutical R&D Co., Ltd
Contact:+86-18653953873
Address:West First of Yufeng Road, Yishui County
Doi:10.1021/jo00372a002
(1986)Doi:10.1002/anie.202003219
(2020)Doi:10.1021/ja01126a070
(1952)Doi:10.1016/j.tetlet.2008.05.013
(2008)Doi:10.1055/s-1986-31472
(1986)Doi:10.1002/ejoc.200701024
(2008)