57985-62-3Relevant academic research and scientific papers
Enantioselective carbometalation of cinnamyl derivatives: New access to chiral disubstituted cyclopropanes - Configurational stability of benzylic organozinc halides
Norsikian, Stephanie,Marek, Ilan,Klein, Sophie,Poisson, Jean F.,Normant, Jean F.
, p. 2055 - 2068 (2007/10/03)
A stoichiometric or catalytic amount of (-)-sparteine can serve asa promoter for the enantioselective carbolithiation of cinnamyl derivatives by primary and secondary organolithium compounds. The enantiofacial choice of the addition reaction is dependent on the stereochemistry of the initial double bond. The resulting benzylic organolithium compounds can be derivatized to a linear phenylated chain that bears two contiguous stereogenic centers with given configurations. The use of the dimethyl acetal of the (E)-cinnamyl alcohol allows the highest enantioselective carbolithiation and by simply warming the reaction mixture to room temperature, the resulting benzylic organo-lithium intermediate undergoes a 1,3-elimination to give the chiral disubstituted cyclopropane in high enantiomeric excess (90-95% ee). Another significant finding is the observation that the Li-Zn transmetalation in a benzylic species occurs with inversion of configuration, and the corresponding acyclic benzylic zinc halides have observable configurational stability at - 30°C.
ANCHORING SUBSTITUTION IN ACYCLIC FRAGMENTS. A TOPICAL BASIS FOR ENHANCED DIASTEREOFACIAL SELECTION IN THE DIELS-ALDER REACTION TO CHIRAL ACRYLATES
Corte, Filip A. J. De,Clercq, Pierre J. De
, p. 493 - 504 (2007/10/02)
Chiral acrylates 4a, 4b and 4c, derived from primary alcohols with a single stereogenic centre, were studied for possible diastereoface differentiation in their Lewis acid catalyzed Diels-Alder reaction with cyclopentadiene.No relevant diastereomeric exce
