Enantioselective Organocatalytic Formal [3 + 3]-Cycloaddition of α,β-Unsaturated Aldehydes and Application to the Asymmetric Synthesis of (−)-Isopulegol Hydrate and (−)-Cubebaol
作者:Bor-Cherng Hong、Ming-Fun Wu、Hsing-Chang Tseng、Ju-Hsiou Liao
DOI:10.1021/ol060486+
日期:2006.5.1
[reaction: see text] The first highly enantioselective organocatalyzed carbo [3 + 3] cascade cycloaddition of alpha,beta-unsaturated aldehydes is reported. Using this methodology, crotonaldehyde is converted to 6-hydroxy-4-methylcyclohex-1-enecarbaldehyde, which is used in the synthesis of (-)-isopulegol hydrate, (-)-cubebaol, and p-tolualdehyde as well as (-)-6-hydroxy-4-methyl-1-cyclohexene-1-methanol
[反应:见正文]报道了第一个高度对映选择性的有机催化碳[3 + 3]α,β-不饱和醛的级联环加成反应。使用这种方法,巴豆醛被转化为6-羟基-4-甲基环己-1-烯醛,用于合成(-)-异胡薄荷醇水合物,(-)-立方丁香酚和对-甲苯甲醛以及(-) -6-羟基-4-甲基-1-环己烯-1-甲醇乙酸酯,是番茄总碱生物碱麦角丙氨酸全合成的中间体。其他的α,β-不饱和醛通过正式的[4 + 2]反应生成手性环己二烯。