2-(Diphenylphosphino)benzoyl-Substituted Calix[4]arene: Efficient Organocatalyst in Aza-Morita-Baylis-Hillman Reaction of N-Sulfonated Imines with Methyl Vinyl Ketone
A novelbifunctionalorganocatalyst 5,11,17,23-tetrabutyl-25-[2-(diphenylphosphino)benzoate]-26,27,28-trihydroxycalix-[4]arene (LB3) was synthesized and applied to promote the aza-Morita-Baylis-Hillman (aza-MBH) reaction of N-sulfonated imines with methyl vinyl ketone. It was found that in the presence of acidic additives the reaction rate could be accelerated to give aza-MBH adducts in good to excellent
For the first time, the aza-Morita-Baylis-Hillman reaction of N-sulfonated imines with methyl vinyl ketone was catalyzed by 5,11,17,23-tetrabutyl-25-(diphenylphosphinomethoxy)-26,27,28-trihydroxycalix[4]arene (LB1), an air-stable, easily isolated and reusable catalyst. Great acceleration of the reaction was observed and the aza-Morita-Baylis-Hillman adducts were produced in excellent yields within short reaction time.
Switchable pyrrole-based hydrogen bonding motif in enantioselective trifunctional organocatalysis
作者:Sviatoslav S. Eliseenko、Fei Liu
DOI:10.1016/j.tet.2018.12.016
日期:2019.1
Pyrroles are versatile chemical motifs for molecular recognition or ligand design but their utility as catalytic components are underexplored. We incorporated a pyrrole motif into our acid-switchable, MAP-based trifunctional organocatalytic system. The switching-on of this system by an external Brønstedacid, 3-methyl benzoic acid, presented proficient catalysis in both aza-Morita–Baylis–Hillman (MBH