Tin(IV) chloride-catalyzed formal [3 + 2] cycloadditions of 5-alkoxy-2-(p-methoxyphenyl)- or 2-phenyloxazoles with diethyl oxomalonate gave 2-oxazoline-4,5,5-tricarboxylates in high regioselectivity. 4-Substituted 5-alkoxy-2-methyloxazoles showed a trend to shift the regioselectivity to offer more 3-oxazoline-2,5,5-tricarboxylates in terms of regioselectivity than 2-oxazolines.
氯化锡 (IV) 催化的 5-烷氧基-2-(对
甲氧基苯基)-或 2-苯基
恶唑与氧代
丙二酸二乙酯的缩
甲醛 [3 + 2] 环加成反应以高区域选择性得到 2-
恶唑啉-4,5,5-
三羧酸酯。4-取代的 5-烷氧基-2-甲基
恶唑显示出改变区域选择性的趋势,在区域选择性方面提供比 2-
恶唑啉更多的 3-
恶唑啉-2,5,5-
三羧酸盐。