Direct Asymmetric Michael Reaction of α,β‐Unsaturated Aldehydes and Ketones Catalyzed by Two Secondary Amine Catalysts |
| |
| Authors: | Prof. Dr. Yujiro Hayashi Nariyoshi Umekubo |
| |
| Affiliation: | 1. http://www.ykbsc.chem.tohoku.ac.jp 0000-0002-1838-5389 Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan;2. Department of Chemistry, Graduate School of Science, Tohoku University, Sendai, Japan |
| |
| Abstract: | A direct asymmetric Michael reaction of α,β‐unsaturated aldehydes and ketones proceeded in the presence of two pyrrolidine‐type catalysts, a diphenylprolinol silyl ether and hydroxyproline, to afford synthetically useful δ‐keto aldehydes with excellent diastereo‐ and enantioselectivity. Although there are several iminium ions and enamines in the reaction mixture, the iminium ion generated by the former catalyst reacts preferentially with the enamine generated by the latter catalyst. |
| |
| Keywords: | asymmetric synthesis enamines Michael reaction organocatalysis synthetic methods |
|
|
