39122-19-5Relevant articles and documents
Stereoselective construction of a quaternary carbon substituted with multifunctional groups: Application to the concise synthesis of (+)-ethosuximide
Abe, Tomoaki,Suzuki, Tatsuo,Sekiguchi, Kazuhiko,Hosokawa, Seijiro,Kobayashi, Susumu
, p. 9303 - 9305 (2003)
Synthetically useful β,γ-unsaturated carbonyl compounds having a quaternary carbon at the α-position were prepared with high stereoselectivity by the reaction of a dienolate anion derived from α,β-unsaturated imide having a chiral auxiliary and electrophiles (ethyl acetate and allyl iodide as the C2 and C3 unit, respectively). This method was applied to a short asymmetric synthesis of (+)-ethosuximide.
Diphenylprolinol silyl ether catalyzed asymmetric Michael reaction of nitroalkanes and β,β-disubstituted α,β-unsaturated aldehydes for the construction of all-carbon quaternary stereogenic centers
Hayashi, Yujiro,Kawamoto, Yuya,Honda, Masaki,Okamura, Daichi,Umemiya, Shigenobu,Noguchi, Yuka,Mukaiyama, Takasuke,Sato, Itaru
, p. 12072 - 12082 (2015/03/31)
The asymmetric Michael reaction of nitroalkanes and β,β-disubstituted α,β-unsaturated aldehydes was catalyzed by diphenylprolinol silyl ether to afford 1,4-addition products with an all-carbon quaternary stereogenic center with excellent enantioselectivity. The reaction is general for β-substituents such as β-aryl and β-alkyl groups, and both nitromethane and nitroethane can be employed. The addition of nitroethane is considered a synthetic equivalent of the asymmetric Michael reaction of ethyl and acetyl substituents by means of radical denitration and Nef reaction, respectively. The short asymmetric synthesis of (S)-ethosuximide with a quaternary carbon center was accomplished by using the present asymmetric Michael reaction as the key step. The reaction mechanism that involves the E/Z isomerization of α,β-unsaturated aldehydes, the retro-Michael reaction, and the different reactivity between nitromethane and nitroethane is discussed.
Synthesis of (+)- and (-)-ethosuximides utilizing asymmetric nitroolefination
Nishide, Kiyoharu,Katoh, Takahiro,Imazato, Hitoshi,Node, Manabu
, p. 839 - 845 (2007/10/03)
Both enantiomers of ethosuximide were synthesized from (S)-(-)- and (R)-(+)-2-methyl-2-[(E)-2-nitroethenyl]-γ-butyrolactones (1), which were obtained by asymmetric nitroolefination of α-methyl-γ-butyrolactone, via the lactone carboxylic acid (3).
