Organocatalytic Asymmetric Tandem Michael Addition-Hemiacetalization: A Route to Chiral Dihydrocoumarins, Chromanes, and 4H-Chromenes
Organocatalytic Asymmetric Tandem Michael Addition-Hemiacetalization: A Route to Chiral Dihydrocoumarins, Chromanes, and 4H-Chromenes
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有机催化不对称串联迈克尔加成-半缩醛化：制备手性二氢香豆素、色满和 4H-色烯的途径
DOI：
10.1021/jo101446d
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发表时间：
2010-10-15
影响因子：
3.6
通讯作者：
Gong, Yuefa
中科院分区：
文献类型：
--
作者：
Lu, Dengfu;Li, Yajun;Gong, Yuefa
研究了脂肪醛与（L）-2-（2-硝基乙烯基）苯酚的不对称串联Michael加成-半缩醛化反应，以构建苯并吡喃骨架。很有趣。在不同类型的仲胺催化剂的作用下，反应的非对映体和对映体选择性发生了显著的变化。二苯基脯氨醇甲硅烷基醚7促进了反应，具有优异的对映体选择性（高达99%cc），但具有模型酯的非对映体选择性（2 8 1 - 10）。L，L-prolylprolimol 5c为最佳菌种。显示出高催化活性。良好的对映选择性（高达89%ee）。各种脂肪醛和取代的（L）-2-（2-硝基乙烯基）苯酚在该串联反应中被证明是良好耐受的。此外，在上述反应中产生的色满-2-醇3可以方便地转化为具有合成和生物学意义的手性二氢香豆素色满。和4H-色烯衍生物
Asymmetric tandem Michael addition -hemacetalization between aliphatic aldehydes and (L)-2-(2-nitiovinyl)phenols was investigated for constructing benzopyran backbones. Interestingly. the diastereo- and enantioselectivities changed markedly when the reaction was mediated by different types of secondary amine catalysts The diphenylprolinol silyl ether 7 promoted the reaction with excellent enantioselectivitics (up to 99% cc) hut with model ate diastereoselectivitics (2 8 1 to 10) Prolylprolinols are another type of efficient catalyst Among them. L,L-prolylprolimol 5c is identified as the optimal species. showing high catalytic activity. good enantioselectivities (up to 89% ee). and excellent diasereoselectivities (up to 50 1 dt) Various aliphatic aldehydes and substituted (L)-2-(2-nitrovinyl)phenols were proven to he well tolerated in this tandem reaction In addition the chroman-2-ols 3 yielded in the above reactions could he conveniently transformed to synthetically and biologically significant chiral dihydrocoumarin chroman. and 4H-chromene derivatives