Asymmetric 1,3-Dipolar Cycloaddition of N-Metalated Azomethine Ylides to Methyl (<i>S</i>)-2-(<i>p</i>-Tolylsulfinyl)acrylate. Synthesis of Optically Pure 2,4,5-Trisubstituted 2,5-Dihydro-1<i>H</i>-pyrroles
作者:José Luis García Ruano、Amelia Tito、M. Teresa Peromingo
DOI:10.1021/jo010797s
日期:2002.2.1
The first 1,3-dipolar reaction of azomethine ylides with optically pure vinyl sulfoxide are reported. The presence of the sulfinyl group increase the reactivity of the acrylate moiety as a dipolarophile, and the reactions evolve with complete regio- and endo-selectivities. Nevertheless, mixtures of the two diastereoisomers 4 and 5 (75-88% de) resulting from the anti dipole/s-cis dipolarophile and syn
报道了甲亚胺基化物与光学纯的乙烯基亚砜的第一1,3-偶极反应。亚磺酰基的存在增加了丙烯酸酯部分作为双极性亲和剂的反应性,并且反应以完全的区域选择性和内选择性形成。然而,分别获得了两种非对映异构体4和5的混合物(75-88%de),其分别来自反偶极/ s-顺式偶极亲和法和顺偶极/ s-反式偶极亲和法。立体选择性可以通过使用THF或MeCN作为溶剂或通过更改MeCN中的反应温度来控制。分离环加合物后,通过热解脱亚磺酰化容易获得光学纯的2,5-二氢-1H-吡咯。