Hydrogen azide-amine systems as an azide nucleophile for substitutions of sulfonates, halides, and vicinal disulfonates
摘要:
Hydrogen azide-alkylamine combination turned out to ensure the displacement of simple primary or secondary sulfonates, halides, and vicinal disulfonates with an azido-group in which an enhanced reactivity is generally achieved as compared with a case of traditional alkali metal azides.
Chiralbisphosphazides complexed with lithium salts efficiently catalyze the direct enantioselective 1,4-addition of dialkyl malonates to acyclic enones. Spectroscopic studies on the stoichiometry of the bisphosphazide and lithium salt have indicated the formation of a 1:1 species as the active enantioselectivecatalyst. It is suggested that the catalyst generates a complex of the protonated phosphazide
Synthesis of homochiral amino alcohols, aziridines and diamines via homochiral cyclic sulphites
作者:Braj B. Lohray、Jaimala R. Ahuja
DOI:10.1039/c39910000095
日期:——
Vicinal diols react with thionyl chloride to give 1,2-cyclic sulphites in quantitative yield, which undergo facile ring opening by lithium azide in dimethylformamide to yield azido alcohols and the latter in turn have been stereoselectively transformed into amino alcohols, aziridines and diamines.
An Efficient and Practical Route to Enantiomerically Pure (+)-(1<i>R</i>,2<i>R</i>)- and (-)-(1<i>S</i>,2<i>S</i>)-1,2-Diphenylethane-1,2-diamines
作者:D. Pini、A. Iuliano、C. Rosini、P. Salvadori
DOI:10.1055/s-1990-27082
日期:——
The synthesis of the title compounds is easily achieved by the asymmetric Sharpless dihydroxylation of trans-stilbene to the corresponding enantiomerically pure diols. The conversion of the diols to the di-p-toluenesulfonates and subsequent reaction with sodium azide affords the diazides, which are reduced by lithium aluminum hydride to the optically pure 1,2-diamines.