Recent achievements in intermolecular sp3 C–H bond functionalization of organic compounds by superelectrophilic trihalomethyl metal complex

• With CBr3+·Al2Br7−, functionalization of sp3 C–H bond in organics is regioselective.
• New classes of branch products with remote functional groups were synthesized.
• One-pot bifunctionalization of bromoadamantanes and adamantanes was achieved.

Selective, one-pot sp3 C–H bond functionalization of an alkyl unit in functional organic compounds opens the unique possibility for the synthesis of desired bifunctional compounds from available compounds. A remarkable success of this field in last decades was connected mostly with the applications of transition metal compounds and radical systems as catalysts. By contrast, until the last decade, the examples of intermolecular functionalization of sp3 C–H bonds in organics by superelectrophiles were very rare and limited to the application of proton acids. However the use of potent superelectrophiles opens a unique perspective for organic synthesis because superelectrophiles (or radical systems in electrophilic media) are the only systems able to induce this functionalization affording not easily accessible branched products with new functional groups remote from the original functionalities. This review demonstrates the application of superelectrophilic complex CBr3+·Al2Br7− for regioselective remote functionalization of available organic compounds, such as n-alkyl acetates, methyl n-alkyl ketones, n-alkyl alkanoates, and adamantanes. With CBr3+·Al2Br7−, the first one-pot synthesis of new classes of branch products containing remote functional groups has been achieved. The superelectrophile CBr3+·Al2Br7− with breaking activity can be considered as non classical ionic organometallic complex, wherein dimeric anion Al2Br7− stabilizes trihalomethyl cation.

CBr3+·Al2Br7− has been successfully applied for regioselective functionalizations of sp3 C–H bonds in organics and the first one-pot synthesis of new groups of branch functional n-alkyl acetates, methyl n-alkyl ketones, and n-alkyl alkanoates containing remote functional groups, as well as the first functionalizations and bifunctionalizations of adamantanes have been achieved.Figure optionsDownload as PowerPoint slide