Selective C-H Activation of Aliphatic Hydrocarbons under Phase-Transfer Conditions

Abstract

Bromination of aliphatic hydrocarbons with NaOH/CBr4 under phase‐transfer conditions selectively gives the tertiary bromide. In the absence of a tertiary C–H bond in the molecule, a secondary bond will be activated (see reaction equation). This conceptionally new system for aliphatic C–H activation very likely relies on the initiation of single‐electron transfer followed by a radical substitution with unusually high regioselectivity.

Bromination of hydrocarbons with CBr4, initiated by light-emitting diode irradiation

“…However, the direct bromination of non-activated C–H bonds is still a challenging task. Although Br 2 [13], CBr 4 [18–20], R 4 NBr [21–22] and LiBr [23] have been reported to serve as bromine sources for the bromination of saturated hydrocarbons, these reactions exhibit low selectivity or reactivity. Efficient bromination using Br 2 as a bromine source combined with a stoichiometric base [24], an excess of MnO 2 [25], or a catalytic amount of Li 2 MnO 3 [26] has been reported to give high reactivity and selectivity.…”

Ritter reaction-mediated syntheses of 2-oxaadamantan-5-amine, a novel amantadine analog

“…In turn 9, may be accessible from two already known 2-oxaadamantane derivatives, namely 8 and 12. 7,8 When we applied the Jirgensons' modification of the classical Ritter reaction to 8, 9 we recovered most of the starting material, along with an unseparable mixture of the expected chloroacetamide 9 and the corresponding bromoacetamide, 10, as evidenced by GC/MS analysis. As it is known that alcohols behave better in the Ritter reaction, we attempted to obtain 11 from the known alcohol 12.…”

Derivatization of diamondoids for functional applications

“…50 Most of these approaches to synthesize adamantane derivatives are based on the selective functionalization of tertiary C-H bonds in adamantane at the bridgehead positions. 51,52 Herein, we summarize the representative approaches to synthesize the four most typical adamantane derivatives: bromide, hydroxyl, amine, and carboxyl substituted adamantane. 51 Many methods have been developed to activate the ternary C-H bonds of adamantane.…”

“…Schreiner et al 52 invented a highly selective method for the direct bromination of adamantane under phase-transfer conditions. Adamantane and tetrabromomethane were refluxed at 40 1C in the presence of CH 2 Cl 2 and 50% aqueous NaOH using triethylbenzylammonium chloride as the phase transfer catalyst to prepare adamantyl bromide.…”