40950-21-8Relevant academic research and scientific papers
Mechanistic Definition of Trimethylstannylation of 1,4-Dihalobicycloheptanes: Bridgehead Nucleophilic Substitution Mediated by the Intermediacy of Radicals, Radical Anions, Carbanions, and Propellane
Adcock, William,Gangodawila, Hemakanthi
, p. 6040 - 6047 (2007/10/02)
A series of 1,4-dihalobicycloheptanes (2; X=Y=halogens) have been synthesized, characterized, and treated with (trimethylstannyl)lithium (Me3SnLi) in the absence and presence of tert-butylamine (TBA).The product distributions of these reactions have been established by 13C and 119Sn NMR spectroscopy and vapor-phase chromatographic analyses.The results clearly indicate that a polar mechanism involving the formation of a carbanion can compete effectively in these systems against a free-radical chain process (SRN1).The latter mechanism was previously shown to dominate the stannlyation reactions of 1,4-dihalobicyclooctanes (1; X = Y = halogens).Most of the initially formed (4-halo(X)bicyclohept-1-yl)lithium derivatives (2; X = halogen, Y = Li) collapse partially (X = Cl) or completely (X = Br and I) to yield the highly reactive propellane, which serves as a transient intermediate in the stannylation process.Most importantly, the competition between the radical and polar mechanisms in 2 is shown to be dependent not only on the nature of the leaving group (Y = Br or I) but also on the substituent (X = H, F, Cl, Br, or I).Factors governing the partitioning between the two mechanisms are considered.
Photoelectron Spectra of Symmetrical 1,4-Dihalonorbornanes
Honegger, Evi,Heilbronner, Edgar,Hess, Nicole,Martin, Hans-Dieter
, p. 2927 - 2939 (2007/10/02)
The He(Iα) photoelectron spectra of 1,4-dihalonorbornanes (2 - 4) and of 1-bromonorbornane (5) have been recorded.Their assignment is based on results derived from recently proposed equivalent bond orbital treatment which has now been adapted to include halogen atoms and to account for spin-orbit coupling.
