Competing Regiodirecting Effects of Ester and Aryl Groups in [3+3] Cyclocondensations of 1,3-Bis(trimethylsilyloxy)-1,3-butadienes: Regioselective Synthesis of 3-Hydroxyphthalates and 2-Hydroxyterephthalates
作者:Mohanad Shkoor、Olumide Fatunsin、Abdolmajid Riahi、Mathias Lubbe、Stefanie Reim、Muhammad Sher、Alexander Villinger、Christine Fischer、Peter Langer
DOI:10.1002/ejoc.200901373
日期:2010.7
es are prepared by regioselective chelation-controlled cyclization of 1,3-bis(silyloxy)-1,3-butadienes with 4-silyloxy-2-oxo-3-butenoates derived from acetylpyruvates. The employment of silylated benzoylpyruvates instead of acetylpyruvates results in a regioselectivity change and the formation of 6-aryl-2-hydroxyterephthalates. The cyclization of 1,3-bis(silyloxy)-1,3-butadienes with 4-ethoxy-2-oxo-3-butenoates
3-Hydroxy-5-methylphthalates 是通过 1,3-双(甲硅烷氧基)-1,3-丁二烯与衍生自乙酰丙酮酸的 4-甲硅烷氧基-2-氧代-3-丁烯酸酯的区域选择性螯合控制环化反应制备的。使用甲硅烷基化苯甲酰丙酮酸盐代替乙酰丙酮酸盐导致区域选择性变化和 6-芳基-2-羟基对苯二甲酸酯的形成。1,3-双(甲硅烷氧基)-1,3-丁二烯与 4-乙氧基-2-氧代-3-丁烯酸酯的环化反应很容易通过烯醇醚与 2-氯-2-氧代乙酸甲酯的缩合获得,提供了一种方便的2-羟基对苯二甲酸酯和 3-羟基邻苯二甲酸酯的方法取决于二烯的取代模式。