89656-88-2Relevant academic research and scientific papers
Asymmetric Alkylation Using Chiral Cyclic Diols to Prepare a Quaternary Carbon
Kato, Keisuke,Suemune, Hiroshi,Sakai, Kiyoshi
, p. 3315 - 3326 (2007/10/02)
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
PREPARATION OF OPTICALLY ACTIVE TRICYCLIC 1,4-DIOXEPIN-5-ONE DERIVATIVES AND ITS APPLICATION TO ASYMMETRIC ALKYLATION
Kato, Keisuke,Suemune, Hiroshi,Sakai, Kiyoshi
, p. 413 - 424 (2007/10/02)
Chiral bicyclic α,β-unsaturated lactones (6a,b and 8a,b) were easily synthesized from chiral cyclic diols (2-4) and cyclic β-keto esters (1a,b).Alkylation of 8b proceeded in a highly diastereoselective manner to afford a quaternary carbon.
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
Ando, Kaori,Takemasa, Yataka,Tomioka, Kiyoshi,Koga, Kenji
, p. 1579 - 1588 (2007/10/02)
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.
Asymmetric Alkylation of Chiral α,β-Unsaturated Lactones
Kato, Keisuke,Suemune, Hiroshi,Sakai, Kiyoshi
, p. 3481 - 3482 (2007/10/02)
Alkylation of 5, prepared from six-membered β-keto ester and (S,S)-cyclohexane-1,2-diol, proceeded in highly diastereoselective manner to afford quaternary carbon. - Key Words: (S,S)-cyclopentane-1,2-diol; (S,S)-cyclohexane-1,2-diol; asymmetric alkylation
