Synthesis and catalysis of aZ-stereoretentive ruthenium carbene catalyst chelated by 2,4,5,7-tetrachloro-1,8-dimercaptonaphthalene for olefin metathesis

Abstract

In this work, 2,4,5,7-tetrachloro-1,8-dimercaptonaphthalene ligand-chelated ruthenium-based carbene olefin metathesis catalyst was synthesized. The synthesized catalyst catalyzed the ring-opening cross-metathesis reactions of norbornene/exo,exo-5-norbornene-2,3-dimethanol with styrene/4-fluorostyrene to obtain high Z-products (97:3 –...

Properties and Catalytic Activity of Hoveyda–Grubbs-Type Catalysts with an S → Ru Coordination Bond in a Six-Membered Chelate Ring

“…Under the same conditions as were used for the abovementioned RCM reactions of N,N-diallyltosylamide (15), the most active catalyst, 11h (R 1 = Naphth-2-yl), provided the highest conversion of N-methallyl-N-allyltosylamide (17), which was, however, only 55% (Figure 8). Therefore, the temperature was raised to 60 °C, which made it possible to expand the range of catalytic activity and to bring the conversion up to 90%.…”

“…In the search for new stable, effective, and highly specific HG-type catalysts, the idea of replacing the oxygen atom with another, better donor has become a dominant trend in metathesis catalyst modification, alongside immobilization and NHC fine-tuning. The first investigations into these trends were launched by the pioneering works of Lemcoff’s group with the development of S -chelates 3 (Figure ), which are analogous to HG-II-type catalysts ( 1 ). , The introduction of a sulfur atom into the five-membered chelate ring − was an obvious alternative to O -chelation due to both their similarities and differences. The most intriguing effect of this replacement was the possibility of cis - trans isomerization of ligands in the target molecules, which causes an unexpected change in the catalyst’s geometry and leads to the more stable cis -dichloro isomer 3- cis (its structure is presented in Figure ), in contrast to the trans -dichloro configuration of the parent HG-II -type catalyst ( 1 ).…”

“…The aforementioned works − not only allow acknowledgment of the impact of replacing the chelating atom in HG-II-type catalysts on their properties, but point the way to future systematic comprehensive research into catalysts with strongly chelating heteroatoms on the benzylidene ligand. In this regard, in recent years, nitrogen-, − phosphorous-, and selenium-chelated Hoveyda–Grubbs-type catalysts have been mentioned in relevant literature.…”