was observed when I was treated with ZnCl2 in refluxing carbon tetrachloride. The bicyclooctadienones2a,b were observed to undergo retro Diels-Alder fragmentation at 138 °C to give hydroxy(or trimethylsiloxy)-phenylethynylketenes3a,b, the only examples of alkynylketenes other than alkynylcyanoketenes to appear in the literature.1 The ketene3 b cycloadds to a variety of ketenophiles, but most interestingly
5,6-二羟基-1,3-二甲氧基-5,6-
二苯基乙炔基-
1,3-环己二烯(1)异常重排为7-羟基-1,4-二甲氧基-2-苯基
乙炔基双环[2.2.2]
辛二烯当我在回流
四氯化碳中用ZnCl 2处理I时,观察到-8-1 (2a)。观察到双
环辛二烯酮2a,b在138°C时发生了逆Diels-Alder断裂,得到羟基(或三甲基甲
硅烷氧基)苯基
乙炔基酮3a,b,这是除炔基
氰基酮以外的炔基烯酮的唯一实例。1烯酮3 b环加成到各种ketenophiles中,但最有趣的是,它与二
苯乙炔发生不同寻常的反应,生成
环戊二酮7和乙氧基
丙炔,生成高度官能化的
苯并呋喃酮8。