106913-99-9Relevant academic research and scientific papers
C2-symmetric bicyclo[3.3.1]nonadiene as a chiral ligand for rhodium-catalyzed asymmetric arylation of N-(4-nitrobenzenesulfonyl)arylimines
Otomaru, Yusuke,Tokunaga, Norihito,Shintani, Ryo,Hayashi, Tamio
, p. 307 - 310 (2007/10/03)
(Chemical Equation Presented) Asymmetric synthesis of diarylmethylamines with high enantioselectivity (95-99percent ee) was realized by use of a new C 2-symmetric diene ligand, (1R,5R)-2,6-diphenylbicyclo[3.3.1]nona-2,6- diene (Ph-bnd*), for th
C2-Symmetric bicyclo[3.3.1]nona-2,6-diene and bicyclo[3.3.2]deca-2,6-diene: New chiral diene ligands based on the 1,5-cyclooctadiene framework
Otomaru, Yusuke,Kina, Asato,Shintani, Ryo,Hayashi, Tamio
, p. 1673 - 1679 (2007/10/03)
As a new type of C2-symmetric chiral diene ligands, which coordinate to a metal by their 1,5-cyclooctadiene framework, we prepared 2,6-disubstituted bicyclo[3.3.1]nona-2,6-diene (bnd*) and bicyclo[3.3.2]deca-2,6-diene (bdd*), and examined their catalytic activity and enantioselectivity for rhodium-catalyzed asymmetric 1,4-addition to α,β-unsaturated ketones and 1,2-addition to N-sulfonylimines. High enantioselectivity of the Ph-bnd* ligand was observed in the addition of phenylboroxine to N-tosylimine and N-4-nitrobenzenesulfonylimine of 4-chlorobenzaldehyde to give phenyl(4-chlorophenyl)methylamines in high enantiomeric excess (98-99% ee).
Synthesis and Structure of Phenyl-Substituted Bicyclononenes
Quast, Helmut,Knoll, Katja,Peters, Eva-Maria,Peters, Karl,Schnering, Hans Georg von
, p. 777 - 784 (2007/10/02)
Addition of one mole of phenyllithium to bicyclononane-2,6-dione (5) affords the hydroxy ketone 6 besides small amounts of the known diol 7.Dehydration of this mixture by sulfuric acid in acetic acid yields the unsaturated ketone 8 and the diene 1 which are separated by chromatography.Wolff-Kishner reduction of 8 furnished the hydrocarbon 2.In the same way, the known ketones exo- and endo-10 are converted into 4.The preferential formation of the less stable endo-10 is interpreted in terms of the relative stability of the conformations required in the intramolecular aldol reaction of diketone 9.The conformations of 4, 8, exo- and endo-10 are determined by X-ray diffraction analyses.Vicinal proton coupling constants are calculated from torsional anlges and compared to those determined in solutions by high-field NMR spectroscopy.Key Words: Bicyclonon-2-ene, phenyl-substituted derivatives of / Conformation of bicyclonon-2-enes
The Reductive ? Bond Cleavage of Barbaralane and 2,6-Diphenylbarbaralane
Trinks, Rainer,Muellen, Klaus
, p. 1481 - 1490 (2007/10/02)
Barbaralane (2) and 2,6-diphenylbarbaralane (8) are synthesized in a straightforward way.The reductive cleavage of the strained hydrocarbons is achieved with alkali metals.The structure of the metallation products, in particular the bonding in the resulting allyl moieties, is elucidated by 1H- and 13C-NMR spectroscopy.The chemical behavior (oxidation, protonation, alkylation) sheds light on the modes of stabilization of the alkali metal derivatives.
SYNTHESIS AND DEGENERATE COPE REARRANGEMENT OF 2,6-DIPHENYLBARBARALANE
Quast, H.,Geissler, E,Mayer, A.,Jackman, L. M.,Colson, K. L.
, p. 1805 - 1814 (2007/10/02)
The oxygen-sensitive 2,6-diphenylbarbaralanes 15 and 16 are synthesized from bicyclononane-2,6-dione (9) via dibromide 14 in four steps with 46 and 54percent overall yield, respectively.Crystalline 2,6-diphenylbarbaralane (15) is yellow at room temperature and decolourizes reversibly on cooling.Accordingly, the UV spectrum of trans-decalin solutions of 15 changes reversibly in the temperature range 295-450 deg K.The bromodiphenylbarbaralane 16 is shown to exist as a single valence tautomer.The 13C chemical shifts of 16 serve as estimates of the analogous shifts in the non-exchanging valence tautomer of 2,6-diphenylbarbaralane (15) itself.The barrier for the degenerate Cope rearrangement of 15 in dichloromethane has been determined from 13C-NMR line width measurements in the temperature range of 169-233 deg K to be ΔG++200 = 21.6 kJ mol-1.Hence phenyl substituents at the termini of the allylic parts of barbaralane accelerate the degenerate Cope rearrangement somewhat more than cyano groups.
