855419-55-5

Upstream product

• 943348-76-3 (2R,3R)-cis-1-(N-1-bis(4-methoxyphenyl)methyl)-2-carboxyethyl-3-phenylaziridine 
• 100-52-7 benzaldehyde 
• 1072879-80-1 (2R,3R)-cis-1-(N-1-bis(4-methoxy-3,5-dimethylphenyl)methyl)-2-carboxyethyl-3-phenylaziridine 
• 233585-42-7 cis-1-benzhydryl-(3R)-phenyl-aziridine-(2R)-carboxylic acid ethyl ester 
• 1072878-82-0 (2R,3R)-cis-1-(N-1-bis(4-methoxy-3,5-di-tert-butylphenyl)methyl)-2-carboxyethyl-3-phenylaziridine 

Downstream Products

• 119677-35-9 (2R,3S)-2-amino-3-hydroxy-3-phenyl-propionic acid ethyl ester 
• 943349-07-3 DL-Trans-4-ethoxycarbonyl-2-oxo-5-phenyl-oxazolidine 
• 127913-31-9 (4S,5R)-2-oxo-5-phenyloxazolidine-4-carboxylic acid 
• 101719-48-6 (S)-3-phenyl-3-(toluene-4-sulfonylamino)-propionic acid ethyl ester 
• 943348-96-7 C₁₂H₁₃NO₄ 

Relevant academic research and scientific papers

Multicomponent catalytic asymmetric aziridination of aldehydes

The first multicomponent catalytic asymmetric aziridination reaction is developed to give aziridine-2-carboxylic esters with very high diastereo- and enantioselectivity from aromatic and aliphatic aldehydes. This new method pushes the boundary of the aziridination reaction to substrates that failed with preformed imines.

Seeking passe-partout in the catalytic asymmetric aziridination of imines: Evolving toward substrate generality for a single chemzyme

The asymmetric catalytic aziridination reaction (AZ reaction) of imines derived from dianisylmethyl (DAM) amine and tetra-methyldianisylmethyl (MEDAM) amine were examined with boroxinate catalysts prepared from both the VANOL and VAPOL ligands. This included an evaluation of different protocols for the preparation of the catalyst. The AZ reaction of DAM and MEDAM imines prepared from nine different aryl and aliphatic aldehydes were examined. The MEDAM imines were superior to the DAM imines in the AZ reaction, giving much higher asymmetric inductions and higher overall yields of aziridines. The MEDAM imines were found to also be superior to the previously studied diphenylmethyl (benzhydryl or Bh) and tetra-tert-butyldianisylmethyl (BUDAM) imines especially for imines derived from aliphatic aldehydes. The average asymmetric induction over the nine different MEDAM imines studied was 97% ee with the VAPOL catalyst and 96% ee with the VANOL catalyst. The MEDAM imines can be deprotected to give N-H aziridines in all cases except for some electron-rich aryl aldehydes. The MEDAM imines are much more reactive than benzhydryl imines, and this was most evident when a diazoacetate ester is replaced by a diazoacetamide. The less reactive diazoacetamides give very low yields in their reactions with benzhydryl imines but high yields with MEDAM imines.

Mapping the active site in a chemzyme: Diversity in the N-substituent in the catalytic asymmetric aziridination of imines

(Chemical Equation Presented) The active site of the aziridination catalyst derived from either the VANOL or VAPOL ligand and B(OPh)3 is larger than expected and can accommodate not only significant substitution on the diarylmethyl unit of the imine but also that alkyl (but not perfluorylalkyl) substituents on the aryl groups lead to enhanced rates and enantioselection. The screen of diarylmethyl N-substituents on the imine revealed that the 3,5-di-tert-butyldianisylmethyl group (BUDAM) gave exceptionally high asymmetric inductions for imines of aryl aldehydes.

Direct access to N-H-aziridines from asymmetric catalytic aziridination with borate catalysts derived from vaulted binaphthol and vaulted biphenanthrol ligands

The asymmetric catalytic aziridination reaction (AZ reaction) of N-dianisylmethylimines (N-DAM-imines) with ethyl diazoacetate is developed with chiral catalysts prepared from triphenylborate and both the vaulted binaphthol (VANOL) and vaulted biphenanthrol (VAPOL) ligands. Catalysts derived from both ligands were equally effective in terms of asymmetric induction, but the VANOL catalyst was slightly faster. Up to 400 turnovers could be achieved with the VANOL catalyst while still maintaining ≥90% ee in the aziridine product. The ligand could be recovered in 95% yield with no loss in optical purity. Excellent asymmetric inductions were observed with arylimines, and although slightly lower inductions were observed for alkyl-substituted imines, the optical purity of the aziridines from all of the imine substrates could be enhanced to ≥ 99% ee with a single crystallization. Methods were developed for deprotection of the N-DAM-aziridines under acidic conditions without causing an acid-promoted opening of the ring. Excellent yields of the N-H-aziridines could be obtained with both alkyl- and aryl-substituted aziridines. Finally, activation of the N-H-aziridines was achieved with Boc, tosyl, and Fmoc groups. The activated aziridines can be converted to β3-amino esters, and unexpectedly, the N-Boc-protected aziridine-2-carboxylate 16b with a phenyl substituent in the 3-position cis to the ester group was found to undergo ring expansion to a mixture of cis- and trans-oxazolidinones.

Novel ozone-mediated cleavage of the benzhydryl protecting group from aziridinyl esters

(Chemical Equation Presented) N-Benzhydryl aziridines-2-carboxylates can be readily obtained from the catalytic asymmetric aziridination reaction from N-benzhydrylimines and ethyl diazoacetate. Cleavage of the benzhydryl group by hydrogenolysis leads to ring opening when R = aryl. Surprisingly, ozone will selectively oxidize the benhydryl group in these aziridines even when R is an aryl group. This allows for a new deprotection strategy for these aziridines whose generality is explored.