benzopyranone (9), formed by cyclization on an o-i-Pr group and ring bromination. No product resulting from reaction of bromine with the double bond was formed. This is ascribed to shielding of the double bond by steric crowding. Attempted etherification of the enolic OH groups did not give the ketene trimethylsilyl or methyl acetals. With diazomethane a bicyclic trienone 13 was formed, presumably by cyclopropanation
研究了 2,2-ditipylethene-1,1-diol (tipyl = 2,4,6-triisopropylphenyl) (1) 溶液的反应,该溶液是 ditipyl
乙酸的烯醇。用 (p-BrC6H4)3N•+SbCl6- 氧化得到
苯并呋喃酮,即五元内酯 (5),通过环上的氧环化和酮化而失去环的芳香性。
溴化也得到 5,大概是通过氧的初始氧化,以及含
溴的六元内酯,苯并
吡喃酮 (9),通过在 oi-Pr 基团上环化和环
溴化形成。没有形成
溴与双键反应的产物。这归因于空间拥挤对双键的屏蔽。尝试将烯醇 OH 基团醚化不会得到
乙烯酮三甲基甲
硅烷基或甲基
缩醛。