Kinetic Resolution of Aziridines via Catalytic Asymmetric Ring-Opening Reaction with Mercaptobenzothiazoles
A highly efficient kinetic resolution of racemic 2-acyl-3-aryl-N-tosylaziridines is achieved through a chiral Lewis acid promoted ring-opening reaction with 2-mercaptobenzothiazoles as the nucleophiles. The chiral N,N′-dioxide-lanthanum complex as catalyst and the 2-mercaptobenzothiazoles as active sulfur nucleophiles are the keys to the success of the reaction. A variety of enantioenriched β-amino thioethers and aziridines are obtained in good yields with good ee values.
Asymmetric aziridination of chalcones catalyzed by a novel backbone 1,8-bisoxazolinylanthracene (AnBOX)-copper complex
Highly enantioselective aziridination of chalcones catalyzed by a novel backbone 1,8-bisoxazolidinylanthracene (AnBOX) and CuOTf with up to > 99% ee and the opposite enantioselectivity compared with the ligands of Evans are described.
Rigid backbone 1,8-anthracene-linked bis-oxazolines (AnBOXes): Design, synthesis, application and characteristics in catalytic asymmetric aziridination
A series of rigid backbone 1,8-anthracene-linked bis-oxazolines (AnBOXes) have been designed, synthesized, and evaluated in the catalytic asymmetric aziridination with [N-(p-toluenesulfonyl)imino]phenyliodinane (PhINTs) as a nitrene source. The results in
Ma, Linge,Jiao, Peng,Zhang, Qihan,Xu, Jiaxi
p. 3718 - 3734
(2007/10/03)
One-pot stereoselective synthesis of anti 3-alkyl and 3-aryl-N-p-tosyl- aziridine-2-ketones and 3-aryl-N-p-tosyl-aziridine-2-carboxylates
An efficient and practical synthesis of N-p-tosyl-aziridine-2-ketones and carboxylates through the use of α,β-unsaturated esters and ketones has been reported. The synthesis was conducted via a one-pot procedure consisting of aminohalogenation and in situ intramolecular SN2 substitution. Triethylamine was found to be an effective base for the in situ cyclization for most substrates. Interestingly, for several enone cases, a slightly modified procedure in which 1.0 equivalent of p-TsNCl2 was slowly added into 2.0 equivalents of enone for aminohalogenation followed by quenching with aqueous Na2SO3 resulted in crude aziridines which were proven to be nearly pure by the crude 1H NMR analysis. Moderate to good yields and excellent anti stereoselectivity were achieved for 21 examples.