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CATALYZED ASYMMETRIC 1,3-DIPOLAR CYCLOADDITION REACTIONS

催化不对称 1,3-偶极环加成反应

基本信息

批准号：
07455355
负责人：
KANEMASA Shuji
金额：
$ 4.93万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

The central purpose of the present project research is the establishment of catalyzed asymmetric 1,3-dipolar cycloaddition methodology, which provides an important entry to stereoselectivesynthesis of heterocyclic compounds. A llylic alcohol substrates have been employed in nitrone and nitrile oxide cycloadditions to give the following findings :1. Benzonitrile oxide cycloadditions with allylic alcohols can be accelerated in the presence of magnesium ions.2. High syn selectivity is observed in the magnesium ion catalyzed reactions of allylic alcohols bearing an alpha-chiral center.3. High regioselectivity is observed in the magnesium ion catalyzed reactions of allylic alcohols bearing gamma-substituents.4. Higher rate acceleration is observed in the magnesium ion caralyzed reactions of more substiituted allylic alcohol substrates. The substrate having two methyl substituents at the gamma-position is 16000 times faster than the unsubstituted one.5. The maximum catalytic cycle of 34 has been recorded in the magnesium ion catalyzed reactions between mesitonitrile oxide and allyl alcohol.6. The presence of a stoichiometric amount of bis (diphenylmethylsilyl) ether of (R,R)-1,2-diphenyl-1,2-ethanediol in the above reaction did not induce any enantioselectivity.7. Other chiral ligands such as bis (diphenylmethyl) ether and bis (triphenylmethyl) ether of (R,R)-1,2-diphenyl-1,2-ethanediol have been employed in the asymmetric reactions to give poor results.8. Use of crotyl alcohol, instead of allyl alcohol, in the magnesium ion catalyzed reactions in the presence of the above chiral ligands result in the inhibition of reaction.9. The nitrone cycloadditions using 3-acryloyl-2-oxazolidinone in the presence of DBFOX-modified magnesium ion are highly enantioselective, but the nitrile oxide cycloadditions can not find rate acceleration either.

本课题研究的主要目的是建立催化不对称1，3-偶极环加成反应体系，为立体选择性合成杂环化合物提供一个重要的切入点。以一种烯丙醇为底物进行硝酮和氧化腈的环加成反应，得到以下结果：1。在镁离子存在下，氧化苄腈与烯丙醇的环加成反应可以得到加速.在镁离子催化的含α-手性中心的烯丙醇反应中观察到了高的顺式选择性.在镁离子催化的含γ-取代基的烯丙醇反应中观察到了高的区域选择性。在镁离子催化的烯丙醇反应中，取代基越多，反应速率越快。在γ-位有两个甲基取代基的底物比未取代的底物快16000倍。在镁离子催化下，均三腈氧化物与烯丙醇反应的最大催化循环为34.在上述反应中存在化学计量量的（R，R）-1，2-二苯基-1，2-乙烷的双（二苯基甲基硅烷基）醚不会诱导任何对映选择性。其他手性配体如（R，R）-1，2-二苯基-1，2-乙烷的双（二苯基甲基）醚和双（三苯基甲基）醚已用于不对称反应中，但结果不佳.在上述手性配体存在下，在镁离子催化的反应中使用巴豆醇代替烯丙醇，导致反应的抑制.在DBFOX修饰的镁离子存在下，硝酮与3-丙烯酰基-2-恶唑烷酮的环加成反应具有高度的对映选择性，但对氧化腈的环加成反应也没有明显的加速作用。