Storage and release of two electrons from an electron-rich carbon–carbon bond: boron mediated reversible coupling of DMAP and 9-azajulolidine

Abstract

Two neutral super electron donors (SEDs) based on C–C single bond have been developed.

A bottleable super-electron-donor for catalytic borylation of aryl halides

“…In this mechanism, the SED molecule I merely triggers the reaction, but not participates in the catalytic cycle. Based on this, it can be assumed that [(dpp-bian)BBr]Li(DME) 3 (E 1/2 = À2.60 V vs. Fc +/0 ), 25 an even stronger reducing agent in comparison to I, should also ''catalyze'' the reaction. In this regard, a catalytic amount of [(dpp-bian)BBr]Li(DME) 3 (5 mol%) was used instead of I for the borylation of iodobenzene (Scheme S6 in ESI †).…”

“…25 The aromatization of the pyridine ring and the electron donating amino groups facilitate the cleavage of the bridging C–C bond and the release of two electrons with a redox potential of E 1/2 = −1.57 V vs. Fc +/0 . 25 Moreover, its ability to reduce iodobenzene and the reversibility between I and two equivalents borenium cation [(dpp-bian)B(DMAP)] + (dpp-bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene, DMAP = 4-(dimethylamino)pyridine) were confirmed in this work. Herein, we report the application of I as a bottleable SED catalyst in the borylation of aryl iodides, bromides, as well as the more challenging chlorides.…”

“…1c). 25 The aromatization of the pyridine ring and the electron donating amino groups facilitate the cleavage of the bridging C-C bond and the release of two electrons with a redox potential of E 1/2 = À1.57 V vs. Fc +/0 . 25 Moreover, its ability to reduce iodobenzene and the reversibility between I and two equivalents borenium cation…”

“…The reduction of Ar-X by SED to afford Ar via ArX À has been verified in our previous work. 25 B 2 pin 2 is activated by EtOK, [38][39][40] which facilitates the departure of [Bpin] À and its reaction with Ar radical, resulting the formation of [Ar-Bpin] À . The radical anion [Ar-Bpin] À exhibits significant reducing power, 41,42…”

Incorporation of Boron into Uranium Metallacycles: Synthesis, Structure, and Reactivity of Boron‐Containing Uranacycles Derived from Bis(alkynyl)boranes

“…Apparently, the electrons transferred to Cu I derive from the dianionic variant of bis(alkynyl)borane. The loss of two electrons leads to the cleavage of the bridged C2−C3 σ‐bond [14] and the regeneration of the original bis(alkynyl)borane 2 b . Therefore, the rearranged bis(alkynyl)boron ligand in complex 3 b is chemically non‐innocent and acts as electron shuttle for multielectron transfer process.…”