was found to be an effective catalyst for the asymmetricaddition of diethylzinc to aldehydes 3 through a screening method for asymmetric catalysts, in which two catalyticasymmetric reactions are connected. The chiral zinc catalyst can be readily prepared catalytically from achiral imine 1 by the chiral rhodium–diene complex mediatedasymmetricaddition of dimethylzinc.
Aziridination and unpredicted homologation reaction of N-sulfonylimines were achieved easily with a very simple, rapid and mild procedure through the use of diazomethane without the presence of any catalyst. The method represents an attractive alternative to metal-catalyzed processes.
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.