Lin Ye, Zhao Bo-Liang, Du Da-Ming
School of Chemistry and Chemical Engineering , Beijing Institute of Technology , 5 South Zhongguancun Street , Beijing 100081 , People's Republic of China.
J Org Chem. 2019 Aug 16;84(16):10209-10220. doi: 10.1021/acs.joc.9b01268. Epub 2019 Jul 31.
The present paper reports a highly stereoselective synthesis of spirooxindole-fused spiropyrazolones through the asymmetric [3 + 2] cyclization reaction of 2-(1-methyl-2-oxoindolin-3-yl)malononitriles with unsaturated pyrazolones under mild conditions. With only a 1 mol % bifunctional squaramide catalyst, a series of chiral dispirocyclic pyrazolone derivatives were attained in high yields (85-97%) with excellent stereoselectivities (up to >99% ee and in all cases >20:1 dr). Moreover, gram-scale synthesis and further transformation of the products were also demonstrated.
本文报道了一种通过2-(1-甲基-2-氧代吲哚啉-3-基)丙二腈与不饱和吡唑啉酮在温和条件下的不对称[3 + 2]环化反应，高效立体选择性合成螺环氧化吲哚并稠合螺环吡唑啉酮的方法。仅使用1 mol%的双功能方酰胺催化剂，即可高产率(85 - 97%)地获得一系列手性双螺环吡唑啉酮衍生物，且具有优异的立体选择性(高达>99% ee，且在所有情况下dr均>20:1)。此外，还展示了产物的克级规模合成及进一步转化。
