300583-35-1Relevant articles and documents
Asymmetric synthesis of β-lactams by intramolecular conjugate addition of serine and cysteine derivatives via memory of chirality
Hyakutake, Ryuichi,Yoshimura, Tomoyuki,Ueda, Yoshihiro,Hayashi, Kazuhiro,Furuta, Takumi,Kawabata, Takeo
, p. 1128 - 1147 (2019/07/31)
– The 4-exo-trig cyclization of axially chiral enolates generated from L-serine and L-cysteine dervatives proceeded predominately over β-elimination to give chiral β-lactams with contiguous tri- and tetrasubstituted carbon centers in up to 96% ee. The key to smooth production of β-lactams is the use of Cs2CO3and CF3CH2OH as a base and a proton source, respectively. A strongly electron-withdrawing Michael acceptor in the substrates was also critical for high enantioselectivity of the β-lactam formation.
Asymmetric synthesis of S-alkyl-substituted (R)-cysteines via a chiral NiII complex of the Schiff's base of dehydroalanine with (S)-2-N-(N-benzylprolyl)aminobenzophenone
Saghiyan,Geolchanyan,Djamgaryan,Vardapetyan,Tararov,Kuz'mina,Ikonnikov,Belokon',North
, p. 1460 - 1463 (2007/10/03)
An efficient procedure was developed for the asymmetric synthesis of S-alkyl derivatives of (R)-cysteine by nucleophilic addition of alkanethiols (BunSH, ButSH, or tert-C5H11SH) to the C=C bond of the dehydroalanine fragment in the Ni11 complex of the Schiff's base of Δ-Ala with (S)-2-N-(N-benzylprolyl)aminobenzophenone [(S)-BPB-Δ-Ala]Ni11. Under conditions of thermodynamic control of the reaction, the diastereomeric excess of the complexes with the (S,R)-configuration was 88 - 96%. After decomposition of the complexes, (R)-S-butylcysteine, (R)-S-tert-butylcysteine, and (R)-S-tert-pentylcysteine were isolated with an enantiomeric purity of >97%.