An efficient asymmetric synthesis of a butan-4-olide having a quaternary asymmetric carbon centre was achieved with up to 97% enantiomeric excess (e.e.) by the 1,7-asymmetric inductive addition of Grignard reagents to the γ-keto esters 4â7, the e.e. of which was highly dependent on the structure of the chelating group of the chiral auxiliaries 1â3.
通过将
格氏试剂1,7-不对称诱导加成到γ-
酮酯4-7,实现了具有四元不对称碳中心的
丁烷-4-醇的高效不对称合成,对映体过量(e.e.)高达97%,其e.e.高度依赖于手性助剂1-3的螯合基团结构。