Stereoselective synthesis of .beta.-lactams by oxidative coupling of dianions of acyclic tertiary amides
摘要:
Tertiary amides RCH2CON(R')CH2Z, where Z is an electron-withdrawing group, were converted into dianions by treatment with 2 equiv of n-butyllithium or tert-butyllithium, and the dianions were oxidized with N-iodosuccinimide (NIS) or a Cu(II) carboxylate to form beta-lactams stereoselectively. The stereochemistry of beta-lactam formation depends on the oxidant; NIS is cis-selective, whereas Cu(II) is nonselective or slightly trans-selective. A high degree of asymmetric induction in the formation of beta-lactams was achieved by using (R)-1-phenylethylamine as a chiral auxiliary. This asymmetric ring closure was applied to the preparation of cis-beta-lactam 31, an intermediate for the synthesis of the monobactam antibiotic carumonam.
Stereoselective synthesis of .beta.-lactams by oxidative coupling of dianions of acyclic tertiary amides
摘要:
Tertiary amides RCH2CON(R')CH2Z, where Z is an electron-withdrawing group, were converted into dianions by treatment with 2 equiv of n-butyllithium or tert-butyllithium, and the dianions were oxidized with N-iodosuccinimide (NIS) or a Cu(II) carboxylate to form beta-lactams stereoselectively. The stereochemistry of beta-lactam formation depends on the oxidant; NIS is cis-selective, whereas Cu(II) is nonselective or slightly trans-selective. A high degree of asymmetric induction in the formation of beta-lactams was achieved by using (R)-1-phenylethylamine as a chiral auxiliary. This asymmetric ring closure was applied to the preparation of cis-beta-lactam 31, an intermediate for the synthesis of the monobactam antibiotic carumonam.
A new synthesis of .beta.-lactams through stereoselective oxidative coupling of the dianions of acyclic amides
作者:Takeo Kawabata、Kenzo Sumi、Tamejiro Hiyama
DOI:10.1021/ja00199a055
日期:1989.8
La synthese du noyau β-lactame se fait via la copulation oxydante d'enolate d'amide utilisant le N-iodo succinimide en tant qu'oxydant
La 合成 du noyau β-内酰胺本身 fait via la copulation oxydante d'enolate d'amide utilisant le N-iodo succinimide en tant qu'oxydant
KAWABATA, TAKEO;SUMI, KENZO;HIYAMA, TAMEJIRO, J. AMER. CHEM. SOC., 111,(1989) N7, C. 6843-6845
作者:KAWABATA, TAKEO、SUMI, KENZO、HIYAMA, TAMEJIRO
DOI:——
日期:——
Stereoselective synthesis of .beta.-lactams by oxidative coupling of dianions of acyclic tertiary amides
作者:Takeo Kawabata、Tatsuya Minami、Tamejiro Hiyama
DOI:10.1021/jo00032a047
日期:1992.3
Tertiary amides RCH2CON(R')CH2Z, where Z is an electron-withdrawing group, were converted into dianions by treatment with 2 equiv of n-butyllithium or tert-butyllithium, and the dianions were oxidized with N-iodosuccinimide (NIS) or a Cu(II) carboxylate to form beta-lactams stereoselectively. The stereochemistry of beta-lactam formation depends on the oxidant; NIS is cis-selective, whereas Cu(II) is nonselective or slightly trans-selective. A high degree of asymmetric induction in the formation of beta-lactams was achieved by using (R)-1-phenylethylamine as a chiral auxiliary. This asymmetric ring closure was applied to the preparation of cis-beta-lactam 31, an intermediate for the synthesis of the monobactam antibiotic carumonam.