Asymmetric induction in an intramolecular [2+2] photocycloaddition within chirally modified zeolite supercages
摘要:
Photoirradiation of 1-cyano-2-(5-methyl-2-oxa-4-hexenyl)naphthalene, included in NaY zeolites along with chiral inductors, such as diethyl tartrate or phenylalaninol, gives an intrarnolecular [2+2] photocycloadduct with a maximum 15% ee. The degree of enantioselectivity was found to depend on the Si/Al ratio, the nature of the cations in the zeolites, the structure of the chiral inductors, and the molar ratio of substrate and chiral inductors. (C) 2009 Elsevier Ltd. All rights reserved.
Irradiation of 2,3-dimethylbut-2-enyl 1-cyano-2-naphthylmethyl ether in the presence of Eu(hfc)3 in benzene site-selectively afforded the (2Ï + 2Ï) intramolecular photocycloadduct at the 1,2-position on the naphthalene ring. On the other hand, allyl 1-cyano-2-naphthylmethyl ether in the presence of Mg(ClO4)2 in acetonitrile gave the photocycloadduct at the 3,4-position as a sole product.
Intramolecular [2+2] and [2+3] photocycloadditions of 2-(2-alkenyloxymethyl)naphthalene-1-carbonitriles and their photocycloreversion using glass-made microreactors were investigated in comparison with photoreactions under conventional batch conditions. Both the efficiency and regioselectivity were improved by use of glass-made microreactors. These results can be explained by thorough absorption of light and outflow of primary product from the reaction system.
Enhanced Efficiency and Regioselectivity of Intramolecular (2π + 2π) Photocycloaddition of 1-Cyanonaphthalene Derivative Using Microreactors
作者:Hajime Maeda、Hirofumi Mukae、Kazuhiko Mizuno
DOI:10.1246/cl.2005.66
日期:2005.1
The intramolecular photocycloaddition of a 1-cyanonaphthalene derivative in microreactors made of poly(dimethylsiloxane) (PDMS) was examined. By using the microreactors and flow system, both the efficiency and regioselectivity increased compared with those under batch conditions.
Photoirradiation of 1-cyano-2-(5-methyl-2-oxa-4-hexenyl)naphthalene, included in NaY zeolites along with chiral inductors, such as diethyl tartrate or phenylalaninol, gives an intrarnolecular [2+2] photocycloadduct with a maximum 15% ee. The degree of enantioselectivity was found to depend on the Si/Al ratio, the nature of the cations in the zeolites, the structure of the chiral inductors, and the molar ratio of substrate and chiral inductors. (C) 2009 Elsevier Ltd. All rights reserved.