Syntheses and Pyrolyses of Benzofuran Analogues of α-Oxo-<i>o</i>-quinodimethane. A Study on Vinylcarbene−Cyclopropene Rearrangement
作者:Pen-Wen Tseng、Su-Wen Yeh、Chin-Hsing Chou
DOI:10.1021/jo702704e
日期:2008.5.1
Flashvacuum pyrolyses (FVP) of benzoic 3-methyl-2-benzofurancarboxylic anhydride (12) and benzoic 2-methyl-3-benzofurancarboxylic anhydride (13) at 550 °C and ca. 10−2 torr both give methylenebenzocyclobutenone (21) as the major product and indenone (22) as the minor one. A mechanism involving generation of α-oxo-o-quinodimethane 11 as the primary pyrolysis product from FVP of 13, followed by elimination
在550°C和约550°C下,对苯甲酸3-甲基-2-苯并呋喃甲酸酐(12)和苯甲酸2-甲基-3-苯并呋喃甲酸酐(13)进行快速真空热解(FVP)。10 -2托既产生亚甲基苯并环丁烯酮(21)作为主要产物,又产生茚满酮(22)作为次要产物。涉及一种机制,涉及从13的FVP生成α-氧代-邻-喹二甲烷11作为主要的热解产物,然后消除CO分子以得到卡宾24,卡宾24经历乙烯基卡宾-环丙烯重排和所得卡宾的环收缩23建议考虑到观察到的结果。所提出的机制是通过(2-苯并呋喃基)甲基- α,α-对FVP氘标记研究进一步支持d 2(苯甲酸28 - d 2)。