Synthesis of highly enantioenriched all-carbon quaternary centers: conjugate additions of chiral organolithium nucleophiles to alpha,alpha-dinitrile beta,beta-disubstituted olefins.
[reaction: see text]. Highly enantioenriched quaternary centers are obtained by the reaction of chiral lithiated intermediates complexed to (-)-sparteine with tetrasubstituted, alpha,alpha-dinitrile activated olefins. Lithiated N-Boc-N-Aryl benzylamine furnishes products with drs from 78:22 to 95:5, with ers exceeding 94:6. Lithiated N-Boc-N-Aryl allylamine reactants provide enecarbamate products with drs from 55:45 to 99:1, with ers ranging from 87:13 to 97:3.
Department of Chemistry, Yonsei University, Wonju 220-710, Korea.
Doo Ok
DO
Jang
Dwight D
DD
Kim
Do Kyu
DK
Pyun
Peter
P
Beak
D000473:Alkanes / Q000138:chemical synthesis*; D000475:Alkenes / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D013034:Sparteine / Q000737:chemistry; D013237:Stereoisomerism
D000473:Alkanes; D000475:Alkenes; D009942:Organometallic Compounds; D013034:Sparteine; D008094:Lithium