A Stereoselective Intramolecular 1,3-Dipolar Nitrone Cycloaddition for the Synthesis of Substituted Chromanes
作者:Qian Zhao、Fusen Han、Donna L. Romero
DOI:10.1021/jo011015y
日期:2002.5.1
A stereoselective intramolecular 1,3-dipolar nitrone cycloaddition useful in the synthesis of chromanes is described. The reaction relies on the use of a chiral auxiliary on the nitrone partner. Key to the success of the reaction is the choice of auxiliary and the choice of Lewis acid catalyst. Utilizing an auxiliary with a pendant coordinating group, and Zn(OTf)(2) as the Lewis acid, diastereoselectivities
描述了可用于苯并二氢吡喃合成的立体选择性分子内1,3-偶极硝酮环加成反应。该反应依赖于在硝酮伴侣上使用手性助剂。反应成功的关键是助剂的选择和路易斯酸催化剂的选择。利用带有侧链配位基团的辅助剂,以及Zn(OTf)(2)作为路易斯酸,可以实现高达22:1的非对映选择性。