Fatme Dahcheh

Synthesis and Reactivity of a CAAC–Aminoborylene Adduct: A Hetero-Allene or an Organoboron Isoelectronic with Singlet Carbenes†

A one-electron reduction of a cyclic (alkyl)(amino)carbene (CAAC)-bis(trimethylsilyl)aminodichloroborane adduct leads to a stable aminoboryl radical. A second one-electron reduction gives rise to a CAAC-aminoborylene adduct, which features an allenic structure. However, in manner similar to that of stable electrophilic singlet carbenes, this compound activates small molecules, such as CO and H2.

Oxidative addition at a carbene center: synthesis of an iminoboryl-CAAC adduct.

The reaction of a cyclic (alkyl)(amino)carbene (CAAC) with dichloro- and dibromobis(trimethylsilyl)aminoborane results in the formation of haloiminoborane-CAAC adducts. When the iodo analogue is used, an oxidative addition at the carbene center affords a cationic iminoboryl-CAAC adduct, featuring a boron-nitrogen triple bond. Similar salts are also obtained by halide abstraction from the chloro- and bromoiminoborane-CAAC adducts. The reactivity of all of these compounds towards CO2 is discussed.