Practical Enantioselective Synthesis of β-Lactones Catalyzed by Aluminum Bissulfonamide Complexes
作者:Thomas Kull、René Peters
DOI:10.1002/adsc.200700084
日期:2007.7.2
practical aluminum-bissulfonamide complex catalyzed enantioselective formation of β-lactones by [2+2] cycloaddition of ketene (generated in situ from acetyl bromide by dehydrobromination) with various α-unbranched and -branched aliphatic aldehydes is presented. The methodology offers the advantage of operational simplicity not only as the ligand synthesis requires just a single sulfonylation step from commercially
提出了一种有效和实用的铝-双磺酰胺铝配合物(通过乙烯酮的[2 + 2]环加成反应(由乙酰溴通过脱氢溴化而原位生成))与各种α-非支链和-支链的脂族醛催化β-内酯的对映选择性形成的研究。该方法提供了操作简单的优点,不仅因为配体合成仅需要来自市售对映体纯的二胺的单个磺酰化步骤。使用10摩尔%的双磺酰胺配体,可以高至极好的收率形成产品,其ee值通常在78%到90%之间。这项工作的关键发现是通过使用1.5:1的铝/配体比率来显着提高速率。