Tailor‐Made Ruthenium‐Triphos Catalysts for the Selective Homogeneous Hydrogenation of Lactams

Abstract

The development of a tailored tridentate ligand enabled the synthesis of a molecular ruthenium-triphos catalyst, eliminating dimerization as the major deactivation pathway. The novel catalyst design showed strongly increased performance and facilitated the hydrogenation of highly challenging lactam substrates with unprecedented activity and selectivity.

Multifaceted catalytic hydrogenation of amides via diverse activation of a sterically confined bipyridine–ruthenium framework

“…The hydrogenation of 3h to azepane proceeded under much milder conditions ( P H2  = 2 MPa), compared with a very recent example in which catalytic (triphos)Ru derivatives were used ( P H2  = ca. 10 MPa) 14 . Although 3h and inter - h might be in an equilibrium even under H 2 40 , the net reaction would proceed via either one of (or both of) the following two pathways involving the same reaction intermediate, N , O -hemiacetal inter - h , which undergoes (Fig.…”

Ruthenium‐Catalyzed Synthesis of Cyclic and Linear Acetals by the Combined Utilization of CO2, H2, and Biomass Derived Diols

“…Decreasing the catalyst loading to 3 μmol significantly increases the total TON (322) of the acetal products, slightly favoring the LA‐1 product over 1,3‐dioxane (entry 2). These results clearly indicate that the catalytic system can be optimized by tailoring of the additive to catalyst ratio and catalyst loading . Moreover, in absence of Al(OTf) 3 co‐catalyst no acetal products could be detected.…”

Hydrogenation of Polyesters to Polyether Polyols

“…[7] Alternatively,t hey must contain an acid-labile ligand, such as BH 4 À or -CH 2 Si(Me) 3 , [8] which also makes them useless for hydrogenation under acidic conditions. In particular the Triphos-based metal complexes have achieved much attention,owing to their broad applicability in reactions including the reduction of esters [12] and of CO 2 , [13] hydrogenation of lactams to cyclic amines, [14] hydrogenolysis of polyesters to diols [4c] andd irect reductive etherification of carboxylic acid esters to ethers (Scheme 1). In particular the Triphos-based metal complexes have achieved much attention,owing to their broad applicability in reactions including the reduction of esters [12] and of CO 2 , [13] hydrogenation of lactams to cyclic amines, [14] hydrogenolysis of polyesters to diols [4c] andd irect reductive etherification of carboxylic acid esters to ethers (Scheme 1).…”