One pot synthesis of optically active 4-isoxazolines by asymmetric addition of alkynylzinc reagents to nitrones followed by cyclization
One pot synthesis of optically active 4-isoxazolines by asymmetric addition of alkynylzinc reagents to nitrones followed by cyclization
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DOI：
10.3987/com-08-11566
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发表时间：
2009-03
期刊：
影响因子：
0.6
通讯作者：
Weilin Wei;Masato Kobayashi;Y. Ukaji;K. Inomata
中科院分区：
文献类型：
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作者：
Weilin Wei;Masato Kobayashi;Y. Ukaji;K. Inomata
-以酒石酸二(叔丁基)(R，R)-酒石酸酯为手性助剂，通过炔基锌试剂与硝酮的不对称加成反应，一锅法合成了光学活性的4-异恶唑啉。二甲基锌的加入加速了环化反应，得到了相应的4-异恶唑啉，ee高达93%。此外，环化的锌中间体可以被甲醛捕获，得到相应的2，3，4，5-四取代4-异恶唑啉，ee为85%。
- One pot synthesis of optically active 4-isoxazolines was achieved by asymmetric addition of alkynylzinc reagents to nitrones utilizing di(t-butyl) (R,R)-tartrate as a chiral auxiliary followed by cyclization. By addition of dimethylzinc, the cyclization step was accelerated to afford the corresponding 4-isoxazolines with up to 93% ee. Furthermore, a cyclized zinc intermediate could be trapped with formaldehyde to give the corresponding 2,3,4,5-tetrasubstituted 4-isoxazoline with 85% ee.