Synthesis of functionalized pyrazole derivatives by regioselective [3+2] cycloadditions of<i>N</i>-Boc-<i>α</i>-amino acid-derived ynones
作者:Eva Pušavec Kirar、Uroš Grošelj、Amalija Golobič、Franc Požgan、Sebastijan Ričko、Bogdan Štefane、Jurij Svete
DOI:10.1515/znb-2018-0013
日期:2018.7.26
Cu-catalyzed cycloadditions of ynones to azomethine imines were regioselective and gave the expected cycloadducts as inseparable mixtures of diastereomers. In some instances, further oxidative hydrolytic ring-opening took place to afford 3,3-dimethyl-3-(1H-pyrazol-1-yl)propanoic acids. Acid-catalyzed cycloadditions of 3-butenone were also regioselective and provided mixtures of diastereomeric cycloadducts, which
摘要 研究了衍生自甘氨酸和 (S)-丙氨酸的炔酮以及一些其他偶极亲和物与偶氮甲碱亚胺、腈氧化物、重氮乙酸酯和叠氮乙酸酯的 [3+2] 环加成反应。从α-氨基酸得到的dipolarophiles,无论是由羧基官能的具有乙炔基溴化镁的减少或通过氨基官能的propiolation。ynones到甲亚胺亚胺的铜催化环加成是区域选择性和得到所需要的cycloadducts非对映体的混合物密不可分。在一些情况下,进一步氧化水解开环发生,得到3,3-二甲基-3-(1H-吡唑-1-基)丙酸的羧酸。3-丁烯酮的酸催化的环加成也非对映体cycloadducts,将其通过色谱法分离的区域选择性和提供的混合物。与烷基diazoacetates,在标题ynones的反应原位形成的腈氧化物,及叔丁基叠氮基,得到作为单一区域异构体的所有cycloadducts。通过核磁共振和X射线衍射建立的所有新颖的化合物的结构。