Substituted β-phenylethylamides undergo smooth intramolecular cyclization to 3,4-dihydroisoquinolines in good to excellent yields when treated with bromotriphenoxyphosphonium bromide at -60 ËC in dichloromethane in the presence of triethylamine. The reaction proceeds under the mildest conditions ever reported for Bischler-Napieralski-type cyclizations. When chlorotriphenoxyphosphonium choride is used, low yields are obtained instead.
被取代的β-苯乙
酰胺类化合物在-60 °C
二氯甲烷中以
三乙胺作为催化剂的条件下,与
溴三苯氧基膦
溴处理时,能以良好至优异的产率顺利进行分子内环化反应生成
3,4-二氢异喹啉。此反应是在目前已报道的比什勒-纳皮亚尔斯基型环化反应中条件最为温和的。而若使用
氯三苯氧基膦
氯时,则产率较低。