An Improved and Stereoselective Route to All-cis-2,6-Disubstituted 4-Hydroxypiperidines from Accessible 4-Substituted 4-N-Benzylaminobut-1-enes
An Improved and Stereoselective Route to All-cis-2,6-Disubstituted 4-Hydroxypiperidines from Accessible 4-Substituted 4-N-Benzylaminobut-1-enes
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从可接近的4-取代的4-N-苄氨基丁-1-烯到全顺式-2,6-二取代的4-羟基哌啶的改进和立体选择性路线
DOI：
10.1055/s-2002-25770
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发表时间：
2002
期刊：
影响因子：
--
通讯作者：
A. Rosas
中科院分区：
文献类型：
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作者：
A. Varlamov;V. Kouznetsov;F. Zubkov;A. Chernyshev;O. V. Shurupova;L. Méndez;A. Rodríguez;Juliette Rivero Castro;A. Rosas
烯丙基溴化镁和亚胺5a-l之间的反应导致相应的4-取代的4-N-苄基-氨基丁-1-烯6a-l，其以区域选择性方式氧化成烯基硝酮7a-l。这些硝酮的分子内1，3-偶极环加成反应得到2-螺环化或2-取代的6-外苯基-1-氮杂-7-氧杂双环（2.2.1）庚烷8a-j，所得双环的N-O键还原断裂得到不同取代的4-羟基哌啶9a-h，产率较高。这种立体选择性的方法允许制备全顺式-4-羟基-6-苯基-2-壬基哌啶（9 i），一种与登氏蛙生物碱241 D相似的类似物.
The reaction between allylmagnesium bromide and imines 5a-l leads to the corresponding 4-substituted 4- N-benzy- laminobut-1-enes 6a-l, which were oxidized in a regioselective manner to the alkenylnitrones 7a-l. The intramolecular 1,3-dipolar cycloaddition of these nitrones gave 2-spiroannulated or 2-substi- tuted 6-exo-phenyl-1-aza-7-oxabicyclo(2.2.1)heptanes 8a-j. Re- ductive cleavage of the N-O bond of the obtained bicycles afforded the diverse substituted 4-hydroxypiperidines 9a-h in good yields. This stereoselective approach allowed the preparation of all- cis-4- hydroxy-6-phenyl-2-nonylpiperidine (9i), a close analogue of den- drobatid frog alkaloid 241D.