New methods and reagents in organic synthesis, 22,1 diphenyl phosphorazidate as a reagent for c-acylation of methyl isocyanoacetate with carboxylic acids
作者:Yasumasa Hamada、Takayuki Shioiri
DOI:10.1016/s0040-4039(00)86794-5
日期:1982.1
Diphenyl phosphorazidate (DPPA) can be used efficiently for the direct C-acylation of methyl isocyanoacetate with carboxylic acids, giving 4-methoxycarbonyloxazoles.
Lithium Enolates in the Enantioselective Construction of Tetrasubstituted Carbon Centers with Chiral Lithium Amides as Noncovalent Stereodirecting Auxiliaries
作者:Kai Yu、Ping Lu、Jeffrey J. Jackson、Thuy-Ai D. Nguyen、Joseph Alvarado、Craig E. Stivala、Yun Ma、Kyle A. Mack、Trevor W. Hayton、David B. Collum、Armen Zakarian
DOI:10.1021/jacs.6b11673
日期:2017.1.11
Lithium enolates derivedfrom carboxylic acids are ubiquitous intermediates in organic synthesis. Asymmetric transformations with these intermediates, a central goal of organic synthesis, are typically carried out with covalently attached chiral auxiliaries. An alternative approach is to utilize chiral reagents that form discrete, well-defined aggregates with lithium enolates, providing a chiral environment