Solvent-dependent Stereochemical Anomaly in the Nucleophilic Addition of Ester-derived Enolate to Bicyclo[3,3,0]octan-2-one System of Diacetone Glucos-3-ulose
作者:Noriaki Yamauchi、Masashi Kishida、Keiju Sawada、Yuji Ohashi、Tadashi Eguchi、Katsumi Kakinuma
DOI:10.1246/cl.1998.475
日期:1998.6
Solvent-dependent anomalous stereoselectivity was observed in the nucleophilic addition of ester enolate to the bicyclo[3,3,0]octane-2-one system of 1,2:5,6-di-O-isopropylidene-α-D-glucofuranulose. While most of the addition took place to the β-face of the carbonyl, the senecioate-derived enolate surprisingly preferred α-face attack in ether solvent in contrast to β-face attack in THF.
在 1,2:5,6-di-O-isopropylidene-α-D-glucofuranulose 的双环[3,3,0]辛烷-2-酮体系中,观察到了酯烯醇与 1,2:5,6-di-O-isopropylidene-α-D-glucofuranulose 的亲核加成中依赖溶剂的反常立体选择性。虽然大部分加成反应发生在羰基的 β 面,但令人惊讶的是,哌啶酸盐衍生的烯醇在乙醚溶剂中更倾向于发生 α 面加成反应,而在四氢呋喃中则不发生 β 面加成反应。