5888-36-8Relevant articles and documents
Evaluation of the chiral DIANANE backbone as ligand for organolithium reagents
Praz, Jezabel,Guenee, Laure,Aziz, Sarwar,Berkessel, Albrecht,Alexakis, Alexandre
scheme or table, p. 1780 - 1790 (2012/07/28)
Novel endo,endo-2,5-diaminonorbonane-derived tertiary C2- symmetrical diamines were synthesized via the one-pot reductive amination of enantiomerically pure norbornane-2,5-dione. These ligands were applied to various catalytic reactions such as asymmetric deprotonation, asymmetric bromine-lithium exchange, and enantioselective addition of aryl- and allkylithium reagents to aromatic aldimines. Copyright
Some new C2-symmetric bicyclo[2.2.1]heptadiene ligands: synthesis and catalytic activity in rhodium(I)-catalyzed asymmetric 1,4- and 1,2-additions
No?l, Timothy,Vandyck, Koen,Van der Eycken, Johan
, p. 12961 - 12967 (2008/03/17)
C2-Symmetric bicyclo[2.2.1]hepta-2,5-dienes with various substituents (R=Bn, i-Bu, c-Hex, allyl) are prepared starting from the corresponding enantiomerically pure bis-triflate (R=OTf). These chiral ligands are tested and compared in rhodium(I)
Experiments towards the formation of 1,6-dehydroquadricyclane and density functional calculations on this and related molecules
Glueck-Walther, Susanne,Jarosch, Oliver,Szeimies, Guenter
, p. 493 - 500 (2007/10/03)
1,6-Dibromoquadricyclane (6) was obtained from norbornadiene (11) by hydroboration, oxidation of the diol 12 to the diketone 14 and its conversion into 2,6-dibromonorbornadiene (20) using tribromodioxaphosphole 16b followed by treatment of the mixture 17/18 with potassium tert-butoxide in DMSO and photocyclization of 20. Reaction of 6 with tBuLi (2 equiv.) led to the formation of 1-bromo-6-lithioquadricyclane 7, the NMR spectra of which were observed up to 0°C. 7 did not lose LiBr to give 4, but could be trapped with H2O and chlorotrimethylsilane to give 21e (53%) and 21f (64%). Reaction of 6 with fBuLi (> 4 equiv.) gave rise to 1,6-dilithioquadricyclane (21c), whose NMR spectra could also be recorded. 21c was converted into the corresponding 1,6-disubstituted quadricyclanes with D2O (87%), chlorotrimethylsilane (92%), dimethyl sulfate (55%), methyl chloroformate (45%), iodine monochloride (62%), and p-toluenesulfonyl chloride (48%). - Density functional calculations using the B3LYP/6-31G* level of theory showed that 1,6-dehydroquadricyclane (4) is a local energy minimum in its singlet electronic state. 4 contains a unique structure with 4 condensed cyclopropane units. The parent hydrocarbons 27 and 28, hitherto unknown, are also local energy minima in their singlet electronic states.
