Catalytic, Interrupted Formal Homo-Nazarov Cyclization with (Hetero)arenes: Access to α-(Hetero)aryl Cyclohexanones
作者:Corey W. Williams、Raynold Shenje、Stefan France
DOI:10.1021/acs.joc.6b01312
日期:2016.9.16
Lewis-acid catalyzed (hetero)arene interrupted, formal homo-Nazarov cyclization have been disclosed. Using SnCl4 as the catalyst, alkenyl cyclopropyl ketones undergo ring-opening cyclization to form six-membered cyclic oxyallyl cations. Subsequent intermolecular Friedel–Crafts-type arylation with various electron-rich arenes and heteroarenes provides functionalized α-(hetero)arylated cyclohexanones
已经公开了路易斯酸催化的(杂)芳烃间断的,正式的均-纳扎罗夫环化的第一个实例。使用SnCl 4作为催化剂,烯基环丙基酮经历开环环化反应,形成六元环氧基烯丙基阳离子。随后的分子间Friedel–Crafts型芳构化与各种富电子芳烃和杂芳烃提供功能化的α-(杂)芳基化环己酮(一种存在于许多天然产物和生物活性化合物中的支架),产率高达88%,非对映异构体比率高达12: 1。由于由酯基引起的极化,在氧烯丙基阳离子的α-碳处发生区域特异性芳基化。