Chiral Transition‐Metal Complexes of Phenanthro‐Annulated N‐Heterocyclic Carbenes – Synthesis and Reactivity

Abstract

A straightforward route to chiral Ag I and Ru II complexes with phenanthrene-fused N-heterocyclic carbene (NHC) ligands is described. The chiral imidazole derivative 1 was prepared in high yield by a simple one-pot reaction starting from commercially available 9,10-phenanthrenequinone. Imidazolium salts 2 and 3 were obtained by alkylation of 1 with alkyl bromides and subsequent anion exchange with Amberlyst A21 resin. Deprotonation with KOtBu led to the correspond-

Metal compounds with rigid polyaromatic ligands. Catalytic consequences

“…12,27,[30][31][32][33][34][35][36] For example, Tapu and coworkers 12 reported the synthesis of the first azolium salt based on phenanthrene. This salt showed a fluorescence quantum yield (Φ) of 0.18.…”

“…The preparation of the palladium and nickel complexes with a family of related NHC in this reaction are still not very common, [32][33][34][35][36][37][38][39][40][41][42][43] and only a few recent examples refer to the use of [NiCp(NHC)X] complexes. [32][33][34]36 In this section we will describe the catalytic studies using the Ni(II) and Pd(II) complexes.…”

“…[32][33][34]36 In this section we will describe the catalytic studies using the Ni(II) and Pd(II) complexes. We will pay special attention to the results shown by the reactions carried out in the presence of π-stacking additives, such as pyrene.…”

“…These conditions were similar to those previously reported by several authors. 32,34,36 The results are summarized in Table 3.3.…”

“…[32][33][34]36 Only complex 2B gave moderate yields for the coupling of 4-bromoacetophenone with phenylboronic acid (entry 6).…”