New chiral diamide ligands containing redox-active hydroquinone groups. Synthesis and results in the palladium(II)-catalyzed 1,4-diacetoxylation of 1,3-dienes

C−C, C−O, C−N Bond Formation on sp2Carbon by Pd(II)-Catalyzed Reactions Involving Oxidant Agents

“…In 2003, Bäckvall and co-workers performed the Pd(II)-catalyzed 1,4-diacetoxylation of 1,3-dienes in the presence of a series of chiral ligands having a 9,10-dihydro-9,10-ethanoanthracene structure. Application of ligand 127 to 2-phenyl-1,3-cyclohexadiene afforded the diacetoxylation product with high regio- and diastereoselectivity and 42% ee (Scheme ) 104 …”

Juglophen: a tetradentate non-innocent electron sponge naphthoquinone-imine ligand and its reduced and oxidized nickel complexes [Ni(jp)]−,0,+

“…This idea of biomimetic modelling was further developed by Bäckvall and co-workers introducing hydroquinone functionalized cobalt salphen complexes as catalysts in aerobic oxidations and introducing quinone-modified chiral palladium complexes for asymmetric 1,3-diene 1,4-diacetoxylation with improved aerobic reoxidation of Pd(0) to Pd(II). 23,24 Fig. 1 Literature known salen-and salphen-type ligands with quinone, naphthoquinone and hydroquinone substructure; (*) chiral bridge.…”

“…1 Literature known salen-and salphen-type ligands with quinone, naphthoquinone and hydroquinone substructure; (*) chiral bridge. [22][23][24] † Electronic supplementary information (ESI) available: NMR spectra, UV/VIS spectra, ATR IR spectra, cyclovoltammograms, crystal structure and DFT calculations. CCDC 2096338-2096340.…”

Asymmetric CuI-Catalyzed Insertion Reaction of 1-Aryl-2,2,2-trifluoro-1-diazoethanes into Si–H Bonds

“…Their inductions in the asymmetric insertion reaction of 1-aryl-2,2,2-trifluoro-1-diazoethanes into the Si–H bond are presented in Scheme . The bite angle is known to have a drastic impact on the enantioselectivity, and free rotation in 1,2-diphenyl-1,2-ethanediamine L2 or in L3 usually allows optimal coordination to copper. Surprisingly, L2 and L3 gave poorer results (60:40 er ).…”