A BICAAC interacts differently with different boranes: Lewis adducts were formed with simple hydroboranes and insertion of the carbene carbon into the B–H bond was observed with more hydridic boranes.

Carbenes are one of the most appealing, well-explored, and exciting ligands in modern chemistry due to their tunable stereoelectronic properties and a wide area of applications. A palladium complex (BICAAC)2PdCl2 with a recently discovered cyclic (alkyl)­(amino)­carbene having bicyclo[2.2.2] octane skeleton (BICAAC) was synthesized and characterized. The enhanced σ-donating and π-accepting ability of this carbene lend a hand to form a robust Pd-carbene bond, which allowed us to probe its reactivity as a precatalyst in Heck-Mizoroki and Suzuki-Miyaura cross-coupling reactions with low catalyst loading in open-air conditions. The diverse range of substrates was explored for both the cross-coupling reactions. To get a better understanding of the catalytic reactions, several analytical techniques such as field-emission scanning electron microscopy, high-resolution transmission electron microscopy, and powder X-ray diffraction were employed in a conclusive manner.

Negishi cross‐coupling reaction of organozinc compounds as nucleophiles with aryl halides has drawn immense focus for C−C bond formation reactions. In comparison to the well‐established library of Pd complexes, the C−C cross‐coupling of this particular approach is largely primitive with nickel‐complexes. Herein, we describe the syntheses of Ni(II) complexes, [(MeBICAAC)2NiX2] (X=Cl (1), Br (2), and I (3)) by employing the bicyclic (alkyl)(amino)carbene (MeBICAAC) ligand. The reduction of complexes 1–3 using KC8 afforded the two coordinate low valent, Ni(0) complex, [(MeBICAAC)2Ni(0)] (4). Complexes 1–4 have been characterized by spectroscopic techniques and their solid‐state structures were also confirmed by X‐ray crystallography. Furthermore, complexes 1–4 have been applied in a direct and convenient method to catalyze the Negishi cross‐coupling reaction of various aryl halides with 2,6‐difluorophenylzinc bromide or phenylzinc bromide as the coupling partner in the presence of 3 mol % catalyst. Comparatively, among all‐pristine complexes, 1 exhibit high catalytic potential to afford value‐added C−C coupled products without the use of any additive. The UV‐vis studies and HRMS measurements of controlled stochiometric reactions vindicate the involvement of Ni(I)−NI(III) cycle featured with a penta‐coordinated Ni(III)‐aryl species as the key intermediate for 1 whereas Ni(0)/Ni(II) species are potentially involved in the catalytic cycle of 4.

The stoichiometric reaction of bicyclic (alkyl)(amino)carbene (BICAAC) with group 15 chlorides, ECl3 (E = P, Sb) to form the Lewis adducts BICAAC:ECl3 (E = P (1), Sb (2)) has been investigated in the present work. The BICAAC smoothly reacts with PPhCl2 to form [BICAAC:PPhCl2] which on in‐situ two electron reduction with 2 equivalents of KC8 afforded the phosphinidene complex, BICAAC=P‐Ph (3). Complete dechlorination of the BICAAC‐ECl3 adducts 1 and 2 with 3 equivalents of KC8 leads to three‐electron reduction to afford low‐valent trans bent bis(BICAAC)E2 complexes (E = P (4) and Sb (5)). These complexes are the first examples of BICAAC adducts with pnictogens and all the complexes have been characterized by different spectroscopic techniques and their solid‐state structure have been elucidated by single crystal X‐ray diffraction.