Back Cover: Planar‐Chiral Secondary Ferrocenylphosphanes (Eur. J. Inorg. Chem. 02/2017)

Abstract

This cover feature shows a diastereomerically pure planar‐chiral secondary ferrocenylphosphane derived from Ugi's amine against a background depicting the Head of Janus, a symbol for the two different features of these compounds: They find application as chiral ligands for metal complexes in asymmetric catalysis, and the corresponding phosphinoborane derivatives could be suitable precursors for the synthesis of chiral P–B polymers by dehydrocoupling. Details are discussed in the article by E. Hey‐Hawkins et al. on page 256 ff (DOI: http://onlinelibrary.wiley.com/doi/10.1002/ejic.201600935/abstract).

Design of a Copper(II) Complex with Tetradentate Bis‐Benzotriazole‐Appended Bipyridine Ligand and its Catalytic Application in A3 Coupling Reaction

“…Among others, Cu‐complexes have been mostly used catalysts for such reactions because of the versatility of Cu‐chemistry, mainly the accessibility of different oxidation states of Cu by tuning the surrounding ligand backbone [10–18] . In this regard, the importance of chelating N‐donor heterocyclic ligands in such multicomponent reaction is noteworthy since these are found to be good π‐accepting as well as good σ‐donating, and therefore are highly effective to stabilize the Cu(I) intermediates, which are the key species in the catalytic cycle of A 3 coupling reactions [16–20] …”

“…Previously, Lykakis and Kostakis recently used coordination polymers of Cu(II) with substituted benzotriazole ligands in catalytic A 3 coupling reaction (Figure 1A). [16] Recently, we became interested to design and study the electronic and chelating effect of several benzotriazole‐based N‐enriched ligands in their transition metal complexes [19–20,26–29] . Inspired by these studies, we rationally employed benzotriazole‐appended N,N‐bidentate and N,N,N‐tridentate suitable chelating ligands for ready access and effective utilization of air‐stable, structurally well‐defined and discrete Cu(II) complexes as precatalysts for A 3 coupling reactions (Figure 1, B–C) [18–20] .…”

“… [16] Recently, we became interested to design and study the electronic and chelating effect of several benzotriazole‐based N‐enriched ligands in their transition metal complexes [19–20,26–29] . Inspired by these studies, we rationally employed benzotriazole‐appended N,N‐bidentate and N,N,N‐tridentate suitable chelating ligands for ready access and effective utilization of air‐stable, structurally well‐defined and discrete Cu(II) complexes as precatalysts for A 3 coupling reactions (Figure 1, B–C) [18–20] . The results showed that the multidentate chelate binding of these ligands to the Cu centre facilitated the catalytic processes, most probably via efficient stereo‐electronic effect exerted to the catalytically active low‐valent Cu(I) centre.…”

Silica-grafted DBU-supported NiCl2: a sustainable heterogeneous catalyst for A3 coupling

“…Plethora of catalysts has been developed for the synthesis of propargylamines employing A 3 strategy[48]. Contemporary literature for A 3 coupling reveals that, homogeneous catalysts such as Cu(II) complexes of benzotriazole, pyridyl, and quinolinyl ligands [49],…”