302800-31-3

Upstream product

• 61-90-5 L-leucine 
• 436850-64-5 (S)-tert-butyl (4-methyl-1-oxo-1-(pyrrolidin-1-yl)pentan-2-yl)carbamate 
• 13139-15-6 N-tert-butoxycarbonyl-L-leucine 
• 56414-88-1 (S)-2-amino-4-methyl-1-(pyrrolidin-1-yl)pentan-1-one 
• 1655-07-8 ethyl 2-oxocyclohexane carboxylate 

Downstream Products

• 69881-57-8 (+)-(R)-2-Oxo-1-(3-oxo-1-butyl)-cyclohexancarbonsaeureaethylester 
• 69881-58-9 (-)-(S)-2-Oxo-1-(3-oxo-1-butyl)-cyclohexancarbonsaeureaethylester 

Relevant academic research and scientific papers

New auxiliaries for copper-catalyzed asymmetric Michael reactions: Generation of quaternary stereocenters at room temperature

Dialkyl amides of L-valine, L-isoleucine, and L-tert-leucine (2) are excellent chiral auxiliaries for the construction of quaternary stereocenters at ambient temperature. Enaminoesters 3, prepared from these auxiliaries 2 and Michael donors 1. undergo a copper-catalyzed asymmetric Michael reaction with methyl vinyl ketone (MVK, 4) to afford products 5 in 70-90% yield and 90-99% ee (enantiomeric excess). The exclusion of moisture or oxygen is not necessary. The auxiliaries 2 are readily available by standard procedures. After workup they can be recovered almost quantitatively.

New chiral auxiliaries for the construction of quaternary stereocenters by copper-catalyzed Michael reactions

The construction of quaternary stereocenters with 95-99% ee at ambient temperatures can be achieved by a copper-catalyzed Michael reaction with the application of α-amino acid amides as chiral auxiliaries [Eq. (1)]. These amides can be obtained in a few steps from the α-amino acids with standard transformations and, after the Michael reaction, they can be quantitatively recovered. Exclusion of water and oxygen is not necessary.