Stereoselectivity in 1,3-Dipolar Cycloaddition Reactions of 2-Benzopyrylium-4-olate with Acrylic Acid Derivatives Catalyzed by Rare Earth Metal Triflates
Stereoselectivity in 1,3-Dipolar Cycloaddition Reactions of 2-Benzopyrylium-4-olate with Acrylic Acid Derivatives Catalyzed by Rare Earth Metal Triflates
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DOI：
10.1055/s-2003-40190
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发表时间：
2003-07
期刊：
影响因子：
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通讯作者：
Kei-ichi Inoue;H. Suga;S. Inoue;Hiroki Sato;A. Kakehi,
中科院分区：
文献类型：
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作者：
Kei-ichi Inoue;H. Suga;S. Inoue;Hiroki Sato;A. Kakehi,
在Rh_2（Ac）_4催化邻甲氧羰基-α-重氮苯乙酮分解生成的2-苯并吡喃-4-醇盐与3-丙烯酰基-2-恶唑嗪酮的反应中，Yb（OTf）_3或Lu（OTf）_3的加入可使反应的外消旋选择性达到87：13。稀土金属离子半径对稀土金属三氟甲磺酸盐催化反应的立体选择性有很大的影响，大于或小于Lu 3 +离子半径的稀土金属离子半径均会降低反应的外消旋选择性。
The addition of Yb(OTf) 3 or Lu(OTf) 3 was found to he quite effective in obtaining exo-selectivity (up to 87:13) in the reaction of 2-benzopyrylium-4-olate, which was generated by the Rh 2 (OAc) 4 -catalyzed decomposition of o-methoxycarbonyl-α-diazoacetophenone, with 3-acryloyl-2-oxazolizinone. The stereoselectivity of the rare earth metal triflate-catalyzed reaction was strongly influenced by the ionic radius of the rare earth metal element, a larger or smaller ionic radius than that of Lu 3 + resulted in decreased exo-selectivity.