4254-59-5Relevant academic research and scientific papers
Diastereoselective conjugate addition of Grignard reagents to a homochiral fumaramide derived from Oppolzer's sultam
Reid, Gary P.,Brear, Kieron W.,Robins, David J.
, p. 793 - 801 (2007/10/03)
Conjugate addition of Grignard reagents to N,N′-fumaroylbis[(2R)- bornane-10,2-sultam] 1 occurred with moderate to high levels of diastereoselectivity. Diastereomeric excesses were estimated by analysis of the 1H NMR spectra of the succinamide mixtures and enantiomeric excesses from 19F NMR spectra of the bis Mosher esters of the diols produced by reductive cleavage of the succinamides. Saponification of the succinamides gave the corresponding (R)-succinic acids with ees up to 92% showing that addition of the Grignard reagents takes place selectively on the re-face of 1.
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.
Asymmetric Synthesis of (R)- and (S)-4-(Substituted Benzyl)dihydrofuran-2(3H)-ones: An Application of the Ruthenium-binap Complex-catalysed Asymmetric Hydrogenation of Alkylidenesuccinic Acids
Shao, Liming,Miyata, Shiro,Muramatsu, Hitoshi,Kawano, Hiroyuki,Ishii, Youichi,et al.
, p. 1441 - 1445 (2007/10/02)
A concise synthesis of (S)- or (R)-4-(substituted benzyl)dihydrofuran-2(3H)-ones (1) with high enantiomeric purity is presented. (S)- or (R)-(Substituted benzyl)succinic acids (6) 97percent enantiomeric excess) were first prepared by Ru2Cl4(R)- or (S
