Solution Structures of Lithium Amino Alkoxides Used in Highly Enantioselective 1,2-Additions
نویسندگان
چکیده
منابع مشابه
Solution Structures of Lithium Amino Alkoxides Used in Highly Enantioselective 1,2-Additions
Lithium ephedrates and norcarane-derived lithium amino alkoxides used to effect highly enantioselective 1,2-additions on large scales have been characterized in toluene and tetrahydrofuran. The method of continuous variations in conjunction with (6)Li NMR spectroscopy reveals that the lithium amino alkoxides are tetrameric. In each case, low-temperature (6)Li NMR spectra show stereoisomerically...
متن کاملNMR spectroscopic investigations of mixed aggregates underlying highly enantioselective 1,2-additions of lithium cyclopropylacetylide to quinazolinones.
The solution structures of mixed aggregates derived from lithium alkoxides and lithium acetylides were investigated as part of a program to develop practical syntheses of quinazolinone-based nonnucleoside reverse transcriptase inhibitors. Low-temperature (6)Li, (13)C, and (15)N NMR spectroscopies reveal that mixtures of lithium cyclopropylacetylide (RCCLi), a (+)-carene-derived amino alkoxide (...
متن کاملSolution structures and reactivities of the mixed aggregates derived from n-butyllithium and vicinal amino alkoxides.
Low-temperature (6)Li, (13)C, and (15)N NMR spectroscopies reveal that mixtures of n-BuLi and (1R,2S)-R'(2)NCH(R)CH(Ph)OLi (ROLi; R = Ph or Me; R'(2)N = pyrrolidino or Me(2)N) in THF/pentane afford a (n-BuLi)(3)(ROLi) (3:1) mixed tetramer and a C(2)-symmetric (n-BuLi)(2)(ROLi)(2) (2:2) mixed tetramer depending on the proportions of the reactants. The corresponding (n-BuLi)(ROLi)(3) (1:3) mixed ...
متن کاملSolution structures of the mixed aggregates derived from lithium acetylides and a camphor-derived amino alkoxide.
Low-temperature (6)Li, (13)C, and (15)N NMR spectroscopies reveal that mixtures of lithium cyclopropylacetylide or lithium phenylacetylide (RCCLi) and a vicinal amino alkoxide derived from camphor (R*OLi) in THF/pentane afford an asymmetric (RCCLi)(3)(R*OLi) mixed tetramer and a C(2)-symmetric (RCCLi)(2)(R*OLi)(2) mixed tetramer depending on the stoichiometries. The corresponding (RCCLi)(R*OLi)...
متن کاملHighly enantioselective conjugate additions of potassium organotrifluoroborates to enones by use of monodentate phosphoramidite ligands.
The use of phosphoramidite ligands in the rhodium-catalyzed asymmetric conjugate addition of potassium organotrifluoroborates to various enones in the absence of water is described. A systematic search for effective catalysts has been performed by use of high-throughput screening methods. Initially, we have screened reaction conditions, catalyst precursors, and focused ligand libraries. In the ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of the American Chemical Society
سال: 2014
ISSN: 0002-7863,1520-5126
DOI: 10.1021/ja412210d