Well-defined coinage metal transfer agents for the synthesis of NHC-based nickel, rhodium and palladium macrocycles

Abstract

Silver(i) and copper(i) complexes of a macrocyclic NHC-based pincer ligand, bearing a central lutidine donor and a dodecamethylene spacer, have been prepared and evaluated under equivalent conditions in transmetallation reactions.

Terminal Alkyne Coupling Reactions through a Ring: Mechanistic Insights and Regiochemical Switching

“…Thef ormation of Z-enynes instead typically evokes vinylidene intermediates. [1] Motivated by these precedents and as part of our research exploring the organometallic chemistry of NHC-based pincer ligands, [10,11] we set about evaluating the use of rhodium complexes containing neutral lutidine-based CNC ligands in terminal alkyne coupling reactions.I np articular,w ew ere interested in ascertaining the capacity of macrocyclic variants for imparting additional reaction control. To this end, we herein describe our work contrasting the reactions of Rh I Scheme 1.…”

Terminal Alkyne Coupling Reactions through a Ring: Mechanistic Insights and Regiochemical Switching

“…[7] Although closely related Rh(PNP) and Rh(PCP) systems demonstrate reduced selectivity,they predominantly give mixtures of only gem-and E-enynes. [1] Motivated by these precedents and as part of our research exploring the organometallic chemistry of NHC-based pincer ligands, [10,11] we set about evaluating the use of rhodium complexes containing neutral lutidine-based CNC ligands in terminal alkyne coupling reactions.I np articular,w ew ere interested in ascertaining the capacity of macrocyclic variants for imparting additional reaction control. Thef ormation of Z-enynes instead typically evokes vinylidene intermediates.…”

“…Thef ormation of Z-enynes instead typically evokes vinylidene intermediates. These novel and appreciably air-sensitive complexes were synthesised by employing reactions of the corresponding Cu I transfer agents [Cu- [11] and fully characterised in solution and the solid state (see the Supporting Information and Figure 1). To this end, we herein describe our work contrasting the reactions of Rh I Scheme 1.…”

“…Selected complexesand proposed mechanistic pathways for the rhodium pincer catalysedf ormation of gem-and E-enynes from terminal alkynes. Ar F = 3,5-(CF 3 [11] and fully characterised in solution and the solid state (see the Supporting Information and Figure 1). Reinforcing the electronic similarities of the CNC-Me and CNC-12 ligands evident from these data, the corresponding Rh I carbonyl derivatives [Rh-…”

Synthesis and complexes of imidazolinylidene-based CCC pincer ligands

“…9 Indeed, in late 2015 when we compiled our review the only known imidazolinylidene-based example to our knowledge was zirconium adduct D. 10 In the intervening time, Chirik and co-workers have prepared iron-based E and demonstrated its ability to selectivity catalyse trituration reactions of C(sp 2 )-H bonds with high efficiently, highlighting the potential versatility of such NHC-pincers. 11 As part of our work developing the organometallic chemistry of NHC-based pincer ligands, which has involved investigation of macrocyclic variants, backbone geometry, atropisomerism and transmetallation methodology, 12 in this report we describe the preparation and preliminary coordination chemistry of imidazolinylidene-based CCC pincer ligands 1 (Chart 2). …”