Nouveau mode de cyclisation de céto-ylures.Application `a une synthèse originale d'acyl-3 hydroxy-4-coumarines et de l'hydroxy-11 benzo-(b) 12[h] xanthone-12
作者:P Babin、J Dunogues、M Petraud
DOI:10.1016/s0040-4020(01)92042-3
日期:1981.1
The thermal decomposition of keto-ylides resulting from the reaction of m - and p-acetoxy benzoyl chlorides with Ph3P=CH-COOMe leads, after saponification to m- and p-phenylpropiolic acid respectively. Ortho substitution by an acyl group generally changes the orientation of the reaction Thus o.-acetoxy-. benzoyloxy- or phenylacetoxy benzoyl chlorides respectively afford:andin satisfactory yields. Saponification
间苯和对乙酰氧基苯甲酰氯与Ph3P = CH-COOMe的反应导致的酮基的热分解分别在皂化为间苯丙酸和对苯丙酸后导致。酰基的邻位取代通常会改变反应的方向。苯甲酰氧基-或苯乙酰氧基苯甲酰氯分别提供:和令人满意的产率。第一种和第二种的皂化得到:这构成了一条新的,方便的途径,可制得3-酰基4-羟基香豆素和11-羟基12 H-苯并(b)氧杂蒽12-。这些最后产物的形成涉及该酰氧基取代基的羰基,而不是如先前在这些系列中观察到的酰氯的羰基。