89656-86-0

Upstream product

• 609-14-3 2-acetylpropanoic acid ethyl ester 
• 100-39-0 benzyl bromide 
• 139616-52-7 ethyl (2S)-2-benzyl-3-<(1S,2S)-2-hydroxycyclohexan-1-yl>oxy-3-butenoate 
• 104372-11-4 N-<2-(ethoxycarbonyl)-1-methylprop-1-enyl>-L-valine tert-butyl ester 
• 340039-86-3 ethyl (2RS)-3,3-<(S,S)-cyclohexane-1,2-dioxy>-2-methylbutanoate 

Downstream Products

• 23239-35-2 (S)-2-amino-2-methyl-3-phenylpropanoic acid 
• 17350-84-4 (R)-2-amino-2-methyl-3-phenylpropanoic acid 
• 116562-88-0 (R)-N-acetyl-α-methylphenylalanine ethyl ester 

Relevant academic research and scientific papers

Catalytic asymmetric alkylation of α-cyanocarboxylates and acetoacetates using a phase-transfer catalyst

The catalytic asymmetric alkylation of α-cyanocarboxylates and acetoacetates with an alkyl halide was performed under phase-transfer conditions to afford compounds which have a chiral quaternary carbon with up to 97% and 94% ee, respectively. As applicati

Asymmetric synthesis of α,α-disubstituted α-amino acids using (S,S)-cyclohexane-1,2-diol as a chiral auxiliary

Diastereoselective alkylation of ethyl 2-methyl- and/or 2-ethylacetoacetates using the (S,S)-cyclohexane-1,2-diol as an acetal chiral auxiliary afforded enol ethers (2a-f and 5a-f) of 92->95% de in 31-70% yields. Removal of the cyclohexane-1,2-diol with BF3-OEt2 afforded β-keto esters (3 and 6) bearing a chiral quaternary carbon. The β-keto esters could be easily converted into optically active α-methylated and/or α-ethylated α,α-disubstituted amino acids (12 and 13) in 21-99% yields using Schmidt rearrangement.

Asymmetric Alkylation Using Chiral Cyclic Diols to Prepare a Quaternary Carbon

Asymmetric alkylation of cyclic and acyclic β-keto ester acetals (4, 5, 13, 14, and 18) with C2-symmetric cycloalkane-1,2-dioxy moiety proceeded in a highly diastereoselective manner to afford enol ethers (9-12, 15-17, 19a-c) with a chiral quat

Stereoselective reactions. XXI. Asymmetric alkylation of α-alkyl β-keto esters to α,α-dialkyl β-keto esters having either (R)- Or (S)-chiral quaternary center depending on the solvent system

Asymmetric alkylation reaction of chiral enamines prepared from α-alkyl β-keto esters and (S)-valine tert-butyl ester leading to either enantiomer is described. Lithiated chiral enamines can be alkylated with alkyl halides in a toluene solvent in the presence of HMPA to give, after hydrolysis, α,α-dialkyl β-keto esters in 70-99%ee. The reactions in the presence of THF, dioxolane, or trimethylamine, instead of HMPA, afford the corresponding antipodes with enantiomeric purities of 44-92%ee. The present method provides a procedure for the synthesis of both enantiomers of α,α-dialkyl β-keto esters in high enantiomeric purities starting from the same chiral enamines.