Reductive Ti-crossed Claisen Condensation between Methyl α-Bromocarboxylates and Acid Chlorides Utilizing a TiCl<sub>4</sub>–PPh<sub>3</sub>–<i>N</i>-Methylimidazole Reagent
Reductive Ti-crossed Claisen condensation between methyl α-bromocarboxylates and acid chlorides utilizing a TiCl4–PPh3–N-methylimidazole reagent proceeded smoothly to give the α-monosubstituted and...
利用 TiCl4–PPh3–N-甲基咪唑试剂,α-溴代羧酸甲酯和酰氯之间的还原性 Ti 交叉克莱森缩合反应顺利进行,得到 α-单取代和...
Chiral lithium binaphtholate for enantioselective amination of acyclic α-alkyl-β-keto esters: Application to the total synthesis of l-carbidopa
A chiral lithium binaphtholate catalyzes the enantioselective amination of α-alkyl-β-keto esters with azodicarboxylates to produce optically active α,α-disubstituted α-aminoacid derivatives in high yields and with good to high enantioselectivities. A stoichiometric amount of lithium hydroxide efficaciously improved both the reactivity and enantioselectivity of amination. The resulting aminated product
作者:Douglass F. Taber、Ritesh B. Sheth、Pramod V. Joshi
DOI:10.1021/jo048011o
日期:2005.4.1
results in high yields of the α-benzoylated ester. Diazo transfer of the benzoylated ester utilizing p-acetoamidobenzenesulfonyl azide affords the α-diazo ester in good yield. Using this simplified procedure, it is easy to prepare gram quantities of α-diazo esters.