| Autor: |
Hans, Andreas C., Becker, Patrick M., Haußmann, Johanna, Suhr, Simon, Wanner, Daniel M., Lederer, Vera, Willig, Felix, Frey, Wolfgang, Sarkar, Biprajit, Kästner, Johannes, Peters, René |
| Předmět: |
|
| Zdroj: |
Angewandte Chemie International Edition; 3/20/2023, Vol. 62 Issue 13, p1-11, 11p |
| Abstrakt: |
A catalyst type is disclosed allowing for exceptional efficiency in direct 1,4‐additions. The catalyst is a zwitterionic entity, in which acetate binds to CuII, which is formally negatively charged and serving as counterion for benzimidazolium. All 3 functionalities are involved in the catalytic activation. For maleimides productivity was increased by a factor >300 compared to literature (TONs up to 6700). High stereoselectivity and productivity was attained for a broad range of other Michael acceptors as well. The polyfunctional catalyst is accessible in only 4 steps from N‐Ph‐benzimidazole with an overall yield of 96 % and robust during catalysis. This allowed to reuse the same catalyst multiple times with nearly constant efficiency. Mechanistic studies, in particular by DFT, give a detailed picture how the catalyst operates. The benzimidazolium unit stabilizes the coordinated enolate nucleophile and prevents that acetate/acetic acid dissociate from the catalyst. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
Plný text