Single‐Face/All‐cis Arene Hydrogenation by a Supported Single‐Site d⁰ Organozirconium Catalyst

Abstract

The single-site supported organozirconium catalyst Cp*ZrBz 2 /ZrS (Cp* = Me 5 C 5 ,B z = benzyl, ZrS = sulfated zirconia) catalyzest he single-face/all-cis hydrogenation of al arge series of alkylated and fused arene derivatives to the corresponding all-cis-cyclohexanes.K inetic/mechanistic and DFT analysis argue that stereoselection involves rapid, sequential H 2 delivery to as ingle catalyst-bound arene face, versus any competing intramolecular arene p-face interchange.

Partial and Total Solvent-Free Limonene’s Hydrogenation: Metals, Supports, Pressure, and Water Effects

“…It is the main reason that why cymene hydrogenation was investigated with all tested catalysts in this study. Cymene hydrogenation over only Pd/C has been investigated by Stalzer et al for comparison with the single-face arene hydrogenation by a supported organozirconium catalyst [44].…”

Solid-State 45Sc NMR Studies of Cp*2Sc–OR (R = CMe2CF3, CMe(CF3)2, C(CF3)3, SiPh3) and Relationship to the Structure of Cp*2Sc-Sites Supported on Partially Dehydroxylated Silica

“…Neutral supports (SiO 2 , Al 2 O 3 ) used in this reaction tend to form M–O x . More Bronsted acidic supports, such as zeolites or sulfated oxides, usually form M---O x ion pairs. − …”

Diastereoselective Rhodium-Catalyzed Hydrogenation of 2-Oxindoles and 3,4-Dihydroquinolones

“…In particular, the desire to escape the restrictions of heteroaromatic compounds has been a major incentive for devising new synthetic methods . The hydrogenation of arenes or heteroarenes represents one of the easiest and most straightforward transformations that leads from aromatic unsaturation to alicyclic or heterocyclic products. , The development of new hydrogenation protocols has flourished over the past ten years, and notable contributions to the field of new defined molecular (pre)­catalysts for selective arene hydrogenations have been made by the groups of Zeng, Glorius, and others …”

“…The major issue here was the stereospecificity of the reactions, which translates into a question of induced diastereoselectivity. It is known that the complete arene ring is not reduced by a simultaneous delivery of six hydrogen atoms but that the reaction occurs stepwise via consecutive syn stereospecific double bond reductions. − The observed selectivity is thus induced by the first stereogenic center(s) created in the hydrogenation process. In previous work, the all- cis selectivity for the hydrogenation was more pronounced in a nonpolar solvent. ,− However, we found for the oxindoles that even in TFE the all- cis products clearly prevailed.…”