497224-60-9Relevant academic research and scientific papers
Solvent choice and kinetic isotope effects (KIEs) dramatically alter regioselectivity in the directed ortho metalation (DoM) of 1,5-dichloro-2,4-dimethoxybenzene
Farmer, Jennifer L.,Froese, Robert D.J.,Lee-Ruff, Edward,Organ, Michael G.
, p. 1888 - 1893 (2015)
The regioselective formation of the 6-lithio derivative of 1,5-dichloro-2,4-dimethoxybenzene (i.e., 12) by directed ortho metalation (DoM) with nBuLi in THF is described. Although literature reports suggest direct deprotonation at C6, a series of time-course and labelling studies has revealed that deprotonation rather occurs exclusively at C3 followed by isomerization of the anion to C6. By contrast, when DoM was performed in Et 2O, deprotonation again occurred selectively at C3, but now no isomerization occurs, and electrophilic capture produces the regioisomer of that produced in THF. In these labeling studies, it has been found that deuterium has an enormous kinetic isotope effect (KIE) that suppresses not only the original DoM reaction at C3 when deuterium is present there, but also suppresses isomerization to C6 when the label is at that site. Remarkably, this "protectinggroup" role of the deuterium is unique to THF; in ether, full deprotonation of the deuterium at C3 was observed.
Palladium-mediated carboxylation of aryl halides (triflates) or benzyl halides using [13C]/[11C]carbon monoxide with tetrabutylammonium hydroxide or trimethylphenylammonium hydroxide
Karimi, Farhad,Langstroem, Bengt
, p. 2256 - 2259 (2007/10/03)
[Carbonyl-11C]carboxylic acids were synthesised using palladium-mediated reaction of [11C]carbon monoxide with aryl halides/triflates and benzyl halides in combination with either tetrabutylammonium hydroxide or trimethylphenylammoni
