Chretien, Jacques R. published the artcileSolvation and steric effects on electrophilic reactivity of ethylenic compounds. 3. Stereo-, regio-, and chemoselectivity of alkene bromination in methanol, Formula: C6H12Br2, the publication is Journal of Organic Chemistry (1993), 58(7), 1917-21, database is CAplus.
The stereo-, regio- and chemoselectivities of the bromination of 30 alkenes bearing 1-3 alkyl groups (Me, Et, Pr, iso-Pr, tert-Bu, neopentyl) were investigated in methanol containing 0.2 M NaBr at 25° under kinetic conditions. The reaction of cis– and trans-alkenes, RCαH:CβHR’, with R more electron-donating than R’, is stereospecific, in agreement with the occurrence of a bromonium ion intermediate. Methanol and bromide ion trap the bridged ion anti with respect to the bridging bromine atom, independently of the crowding of the double bond. In contrast to the usual belief, the anti-Markovnikov regioselectivity of attack by methanol is always favored, even in the absence of bulky substituents; the better a donor R is, the more the nucleophile attacks Cβ. The chemoselectivity dependence on the double-bond substituents is also unexpected; dibromide formation increases with respect to that of methoxy bromide as electron-donation by R and R’ increases, although the increasing carbocationic character of the carbon atoms of the bridged ion should favor trapping of the intermediate by methanol. Analogous trends for the regio- and chemoselectivity dependence on the substituents are observed in the bromination of monosubstituted alkenes, RCH:CH2, via bromonium ions. These results are attributed to a decrease in the pos. charge densities on the carbon atoms of the bridged ions when the ability of the donor substituents to delocalize charge increases. gem-Disubstituted alkenes, RR’C:CH2, and trimethylethylene behave differently as regards the regio- and chemoselectivity. They react 100% Markovnikov and chemoselectively (about 80%) in favor of attack by methanol. It is shown that these selectivities agree fairly well with highly dissym. bromonium ions as intermediates in the bromination of these alkenes.
Journal of Organic Chemistry published new progress about 594-81-0. 594-81-0 belongs to bromides-buliding-blocks, auxiliary class Bromide,Aliphatic hydrocarbon chain, name is 2,3-Dibromo-2,3-dimethylbutane, and the molecular formula is C6H12Br2, Formula: C6H12Br2.
Referemce:
https://en.wikipedia.org/wiki/Bromide,
bromide – Wiktionary