Enantioselective 1,3-Dipolar Cycloadditions of Diazoacetates with Electron-Deficient Olefins
作者:Mukund P. Sibi、Levi M. Stanley、Takahiro Soeta
DOI:10.1021/ol070364x
日期:2007.4.1
[reaction: see text] A general strategy for highly enantioselective 1,3-dipolar cycloaddition of diazoesters to beta-substituted, alpha-substituted, and alpha,beta-disubstituted alpha,beta-unsaturated pyrazolidinone imides is described. Cycloadditions utilizing less reactive alpha,beta-disubstituted dipolarophiles require elevated reaction temperatures, but still provide the corresponding pyrazolines
[反应:见正文]描述了将重氮酯高度对映选择性1,3-偶极环加成至β-取代的,α-取代的和α,β-二取代的α,β-不饱和吡唑烷酮酰亚胺的一般策略。利用反应性较低的α,β-二取代的双极性亲和剂的环加成反应需要升高的反应温度,但仍提供具有优异对映选择性的相应吡唑啉。最后,说明了使用这种环加成法作为关键步骤的有效合成(-)-麦芽糖苷A的方法。