N-Heterocyclic carbenes (NHCs) are commonly prepared by deprotonation of azolium salts using strong anionic bases. This reaction is often unselective, yielding alkali metal NHC complexes or dimerized NHCs. Alternatively, free NHCs are obtained by the dechlorination of 2-chloroazolium salts using electronrich phosphines. PPh 3 , PCy 3 , and PtBu 3 are unsuitable for Cl + abstraction, while the sterically encumbered tris(1,3-tert-butylimidazolidin-2-ylidenamino)phosphine 1 selectively removes Cl + from 2-chloroazolium salts. Since bulky 1 does not bind to metal complexes, it was used for the preparation of NHC complexes via in situ Cl + abstraction from 2-chloroazolium salts. The dechlorination was employed for the site-selective monometallation with Ir I , Ir III , Rh I , Rh III , and Ru II of a bis-NHC precursor composed of a 2-chlorobenzimidazolium and a 2-chlorobenzimidazole group, followed by the preparation of the heterobimetallic Ir III /Pd II complex [18] (BF 4 ) 2 by a dechlorination/oxidative addition reaction sequence.

Highly regioselective cobalt catalyzed [2+2+2] cycloaddition of diynes and monoynes to afford isobenzofuranones in good yields is described. The reaction proceeds in the presence of cheap and readily available cobalt catalyst with a sterically hindered pyridine‐2,6‐diimine ligand. Applicability of the method can also be extended to the synthesis of isoindolinones.

The 4,4'-dimethylenebiphenyl linked symmetric bis-(2-chlorobenzimidazole) 1 and the unsymmetric 2-chlorobenzimidazolium/2-chlorobenzimidazole 2(BF 4 ) have been reacted with one equivalent [Pd(PPh 3 ) 4 ] in oxidative addition reactions. For the symmetric bis-NHC precursor 1, double metallation of both 2chlorobenzimidazole sites to give the dinuclear bis-pNHC complex [3](BF 4 ) 2 was observed. The unsymmetric compound 2(BF 4 ) was only metallated at the 2-chlorobenz-imidazolium site with formation of the mononuclear NHC complex [4](BF 4 ). The remaining 2-chlorobenzimidazole moiety was subsequently metallated in a second oxidative addition reaction with [M-(PPh 3 ) 4 ] (M = Pd, Pt) to give the homobimetallic NHC/pNHC complex [5](BF 4 ) 2 (M = Pd) and the heterobimetallic complex [6](BF 4 ) 2 demonstrating the unique site-selective metallation of the bis-NHC precursor 2(BF 4 ) by two consecutive oxidative additions.

The diastereoselective synthesis of sulfonylated indolines is reported. A palladium-catalyzed dearomative sulfination of (aza)­indole-tethered aryl iodides generates reactive benzylic sulfinates. These intermediates react with electrophiles in a one-pot, two-step process to generate sulfonylated products in good yields and excellent diastereoselectivity. This three-component sequence demonstrates good scalability and can be applied toward the synthesis of sulfonamides. Additionally, further derivatizations of aryl iodide containing products furnish spiro- and alkynylated indoline products.

NHCs werden konventionell durch Deprotonierung von Azoliumsalzen mit starken anionischen Basen synthetisiert. Diese Reaktion ist oft unselektiv und kann zu Alkalimetall-Komplexen der NHCs oder zu dimerisierten NHCs führen. Alternativ können NHCs durch Dechlorierung von 2-Chlorazoliumsalzen mit elektronenreichen Phosphanen erhalten werden. PPh 3 , PCy 3 und PtBu 3 sind ungeeignet für die Cl + -Abstraktion, während das sterisch anspruchsvolle Tris(1,3-tert-butylimidazolidin-2-ylidenamino)phosphan 1 selektiv Cl + von 2-Chlorazoliumsalzen entfernt. Da das sterisch anspruchsvolle 1 nicht an Metallkomplexe bindet, wurde es für die Synthese von NHC-Komplexen durch in-situ-Chloroniumabstraktion von 2-Chlorazoliumsalzen eingesetzt. Die Dechlorierung wurde auch für die regioselektive Monometallierung einer Bis-NHC-Ligandenvorstufe bestehend aus einer 2-Chlorbenzimidazolium-und einer 2-Chlorbenzimidazolgruppe mit Ir I , Ir III , Rh I , Rh III und Ru II eingesetzt, gefolgt von der Synthese des heterobimetallischen Ir III /Pd II -Komplexes [18](BF 4 ) 2 in einer Dechlorierung/Oxidative-Addition-Reaktionssequenz.