Photocyclization reactions. Part<b>3</b>. Synthesis of naphtho[1,8-<i>bc</i>]-furans and Cyclohepta[<i>cd</i>]benzofurans using photocyclization of 8-alkoxy-1,2,3,4-tetrahydro-1-naphthalenones and 4-alkoxy-6,7,8,9-tetrahydro-5<i>H</i>-benzocyclohepten-5-ones
作者:Essam Mohamed Sharshira、Haruki Iwanami、Mutsuo Okamura、Eietsu Hasegawa、Takaaki Horaguchi
DOI:10.1002/jhet.5570330104
日期:1996.1
Photocyclization reactions were carried out on 8-alkoxy-1,2,3,4-tetrahydro-1-naphthalenones (six-membered ring ketones) 4a-g and 4-alkoxy-6,7,8,9-tetrahydro-5H-benzocyclohepten-5-ones (seven-membered ring ketones) 5a-e in acetonitrile. Irradiation of 4a-f gave rearranged naphthyl alcohols 8a-f as major products. In the case of 4g, 2a,3,4,5-tetrahydronaphtho[1,8-bc]furan-2a-ol 6g was obtained. In contrast
在8-烷氧基-1,2,3,4-四氢-1-萘酮(六元环酮)4a-g和4-烷氧基-6,7,8,9-四氢-5 H上进行光环化反应-乙腈中的-苯并环庚烯5-酮(七元环酮)5a -e。辐照4a-f得到重排的萘醇8a-f作为主要产物。在4g的情况下,获得2g,3a,3,4,5-四氢萘并[1,8 - bc ]呋喃-2a-ol 6g。相反,辐照5a -e以良好的产率得到了2,2a,3,4,5,6-六氢环庚[ cd ]苯并呋喃-2a -ols 9a-e。之间的反应性差异4a-g和5a-e归因于六元和七元环的构象。讨论了1,5-双自由基的环化步骤中的构象和取代基效应以及反应途径。