Synthesis of Functionalized 1-Azaspirocyclic Cyclopentanones Using Bronsted Acid or <i>N-</i>Bromosuccinimide Promoted Ring Expansions
作者:Gregory R. Dake、Michaël D. B. Fenster、Paul B. Hurley、Brian O. Patrick
DOI:10.1021/jo0493572
日期:2004.8.1
onic acid or HCl) or N-bromosuccinimide, an electrophilic bromine source. Reactions promoted by N-bromosuccinimide tend to proceed in higher yields (80−95%) and with greater diastereoselectivity (3:1−1:0) compared to those reactions promoted by a Bronsted acid. In addition, N-bromosuccinimide promoted reactions can produce a complementary stereochemical outcome compared to the reactions using Bronsted
氮杂螺环系统存在于多种生物碱中。官能化1- azaspirocyclopentanones(6,7,11,12 - )可以有效地通过的2-(1-羟基环丁基)semipinacol扩环反应构造p -toluenesulfonylenamides(4由任一布朗斯台德酸((促进)小号) - (+ )-10-樟脑磺酸或HCl)或N-溴代琥珀酰亚胺,一种亲电溴源。与由布朗斯台德酸促进的反应相比,由N-溴代琥珀酰亚胺促进的反应倾向于以更高的收率(80-95%)和更高的非对映选择性(3:1-1-1:0)进行。另外,N与使用布朗斯台德酸的反应相比,β-溴代琥珀酰亚胺促进的反应可以产生互补的立体化学结果。