106913-98-8Relevant articles and documents
SYNTHESIS AND DEGENERATE COPE REARRANGEMENT OF 2,6-DIPHENYLBARBARALANE
Quast, H.,Geissler, E,Mayer, A.,Jackman, L. M.,Colson, K. L.
, p. 1805 - 1814 (1986)
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.
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.
