Photochemistry of Bicyclo[2.2.2]oct-7-ene-2,5-diones and the Corresponding 5-Hydroxyimino and 5-Methylene Derivatives
作者:Ming-Shyong Yang、Shyue-Sheng Lu、Chitneni Prasad Rao、Yow-Fu Tsai、Chun-Chen Liao
DOI:10.1021/jo0301191
日期:2003.8.1
1a-c underwent chemoselective oxa-di-pi-methane rearrangement under sensitized conditions and suffered formal ketene extrusion upon direct irradiation. Direct irradiation of 1d afforded 11d via formal ketene extrusion but under sensitization it remained unchanged. Oximes 2a-d suffered ketene extrusion upon direct irradiation and E/Z isomerization under sensitized conditions. On the other hand, 5-methylenebicyclo[2
描述了包含多个发色体系的几种标题化合物1-3的合成和光化学。2,6,6-三甲基环己-2,4-二烯酮(5)与乙炔6a-d的Diels-Alder反应提供了加合物7a-d,该加合物在水解后提供了所需的双环[2.2.2]辛二酮1a-d。 。通过在吡啶中用盐酸羟胺处理由二酮1a-d制得肟2a-d。通过相应二酮1a-d的化学选择性Wittig反应获得5-亚甲基双环[2.2.2] oct-7-en-2-ones 3a-d。双环[2.2.2]辛烯二酮1a-c在敏化条件下进行了化学选择性的oxa-di-pi-甲烷重排,并在直接照射下遭受了正式的乙烯酮挤出。通过正式的乙烯酮挤出,直接照射1d可得到11d,但在敏化作用下,它保持不变。肟2a-d在直接照射下和在敏化条件下的E / Z异构化作用下发生了乙烯酮挤出。另一方面,通常对5-亚甲基双环[2.2.2] oct-7-en-2-one 3a-d进行1,3-酰基