21898-92-0Relevant academic research and scientific papers
Solvent-equilibrated ion pairs from carbene fragmentation reactions
Moss, Robert A.,Zheng, Fengmei,Fede, Jean-Marie,Johnson, Lauren A.,Sauers, Ronald R.
, p. 12421 - 12431 (2007/10/03)
[R+ OC Cl-] ion pairs were generated in methanol/dichloroethane solutions, with R+ as the 1-bicyclo[2.2.2]octyl, 1-adamantyl, or 3-homoadamantyl cation. Ion pairs were produced either by the direct fragmentation of alkoxychlorocarbenes (ROCCl), with R = 1-bicyclo[2.2.2]octyl, 1-adamantyl, or 3-homoadamantyl, or by the ring expansion-fragmentation of R′CH2OCCl, with R′ = 1-norbornyl, 3-noradamantyl, or 1-adamantyl. Correlations of the [ROMe]/[RCl] product ratios as a function of the mole fraction of MeOH in dichloroethane showed that the homoadamantyl chloride ion pairs, produced by either the direct or ring expansion-fragmentations, were identical, solvent- and anion -equilibrated, and precursor independent. Laser flash photolysis experiments gave 20-30 ps as the time required for solvent equilibration and precursor independence. Methanol/chloride selectivities of the (less-stable) 1-adamantyl chloride and 1-bicyclo[2.2.2]octyl chloride ion pairs were not independent of their ROCCl or R′CH2OCCl precursors. Computational studies provided transition states for the fragmentations and for the structures of the ion pairs.
