Enantioselective rhodium catalyzed hydroboration of olefins using chiral bis(aminophosphine) ligands
作者:Jean-Michel Brunel、Gérard Buono
DOI:10.1016/s0040-4039(99)00538-9
日期:1999.4
The synthesis of new chiral bis(aminophosphine) ligands 1–5 was achieved and assessed in the enantioselectiverhodium catalyzed hydroboration of various olefins with catecholborane. Enantioselectivities up to 77% were obtained.
AN ASYMMETRIC SYNTHESIS OF β-FORMYL β-HYDROXY ESTERS
作者:Yoji Sakito、Masatoshi Asami、Teruaki Mukaiyama
DOI:10.1246/cl.1980.455
日期:1980.4.5
Optically active β-formyl β-hydroxy esters are prepared in high enantiomeric excess by treating 2-acyl-1,3-diazabicyclo[3.3.0]octane derivatives, prepared from (S)-2-(substituted aminomethyl)pyrrolidine and phenylglyoxal monohydrate or methyl hydroxymethoxyacetate, with metal enolates of ethyl acetate.
Modular Synthesis of New Bicyclic Carbene Precursors
作者:Jie Li、Jiaqi Yao、Weiping He、Fan Yang、Xiaoming Liu
DOI:10.2174/1570178616666190212125426
日期:2019.10.9
A series of new N-heterocyclic carbene (NHC) precursors, containing bicyclic pyrrolo[1,2- c]imidazole framework, were prepared from N-(tert-butoxycarbonyl)-L-proline (1-Boc-L-proline). The sequential attachment of nitrogen nucleophiles and subsequent ring closure gave the desired bicyclic NHC precursors in good yields. The structures of these new NHC precursors were determined on the basis of spectroscopic
seven chiral azolinium and five functionalized chiral azolinium salts, precursors to N-heterocyclic carbenes, derived from l-proline has been developed. Moderate to good overall yields were obtained. Some NHC dimers and thiones were isolated. X-ray crystal structure determinations of two [Rh-NHC] complexes were also reported. A short and flexible procedure for the preparation of seven chiral azolinium