Hong Bor-Cherng, Wu Ming-Fun, Tseng Hsing-Chang, Liao Ju-Hsiou
Department of Chemistry and Biochemistry, National Chung Cheng University, Chia-Yi, Taiwan, ROC.
Org Lett. 2006 May 25;8(11):2217-20. doi: 10.1021/ol060486+.
[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 acetate, an intermediate in the total synthesis of lycopodium alkaloid magellanine. Other alpha,beta-unsaturated aldehydes give rise to chiral cyclohexadienes via formal [4 + 2] reactions.
[反应：见正文] 报道了首例α,β-不饱和醛的高度对映选择性有机催化碳[3+3]级联环加成反应。采用该方法，巴豆醛可转化为6-羟基-4-甲基环己-1-烯甲醛，其可用于合成（-）-异蒲勒醇水合物、（-）-匙叶桉油醇、对甲苯甲醛以及（-）-6-羟基-4-甲基-1-环己烯-1-甲醇乙酸酯，后者是石松生物碱麦哲伦碱全合成中的一个中间体。其他α,β-不饱和醛通过形式上的[4+2]反应生成手性环己二烯。
