We report the first isolation of phosphine copper boryl complexesspecies pivotal to numerous copper-catalyzed borylation reactions. The reaction of diboron(4) derivatives with copper tert-butoxide complexes of phosphine ligands allows the isolation of the dimeric μ-boryl-bridged Cu­(I) complexes [(iPr3P)­Cu–Bdmab]2 (4) and [(C6H4(Ph2P)2)­Cu–Bpin]2 (6) with Cu···Cu distances of 2.24–2.27 Å (dmab = (NMe)2C6H4, pin = (OCMe2)2)). A slightly more sterically demanding boryl ligand furnishes the unprecedented multinuclear copper boryl complex [(iPr3P)2Cu8(B­(iPrEn))3(OtBu)3] (5), a potential intermediate of the decomposition of an initial Cu­(I) boryl complex (iPrEn = (NiPr)2C2H4). All complexes were characterized by single-crystal X-ray diffraction, NMR spectroscopy, and elemental analysis. DFT computations support the nature of these unique complexes and give insight into their electronic structures.

A series of group 13 complexes of the general type [{(WCA‐IDipp)EX3}Li(solv)] (E=B, Al, Ga, In; X=Cl, Br) that bear an anionic N‐heterocyclic carbene ligand with a weakly coordinating borate moiety (WCA‐IDipp, WCA=B(C6F5)3 and IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) were prepared by the reaction of the respective group 13 trihalides (EX3) with the lithium salt [(WCA‐IDipp)Li ⋅ toluene]. The molecular structures of the BBr3, AlCl3, AlBr3, GaCl3 and InCl3 adducts were established by X‐ray diffraction analyses, revealing the formation of coordination polymers linked by halide‐lithium interactions, except for the indium derivative, which consists of isolated [Li(THF)4]+ and [(WCA‐IDipp)InCl3]− ions in the solid state.

As part of our program on the synthesis and reactivity of the pyrrole-imidazole alkaloids from marine sponges, the synthesis of the 2-azido analog of the key marine natural product oroidin is reported. In addition, desaminooroidin and its alkyne analog were synthesized. Red-Al reduction of a 4-alkynylimidazole intermediate afforded the (E)-alkene, without having to pass via the (Z)-alkene. Coupling of 4,5-dibromopyrrole-2-carboxylic acid with 2-azidoimidazolylprop-2-en-1-amine was best achieved by EDCI-mediated coupling, which was superior to using the corresponding trichloromethylketone. Use of t-BuOK in acetonitrile can be recommended for the coupling of non-azidated alkenyl and alkynylimidazoles. The azido analog of oroidin underwent click cycloadditions to imidazolyltriazoles.