4128-31-8Relevant articles and documents
Regiodivergent Reductive Opening of Epoxides by Catalytic Hydrogenation Promoted by a (Cyclopentadienone)iron Complex
De Vries, Johannes G.,Gandini, Tommaso,Gennari, Cesare,Jiao, Haijun,Pignataro, Luca,Stadler, Bernhard M.,Tadiello, Laura,Tin, Sergey
, p. 235 - 246 (2022/01/03)
The reductive opening of epoxides represents an attractive method for the synthesis of alcohols, but its potential application is limited by the use of stoichiometric amounts of metal hydride reducing agents (e.g., LiAlH4). For this reason, the corresponding homogeneous catalytic version with H2 is receiving increasing attention. However, investigation of this alternative has just begun, and several issues are still present, such as the use of noble metals/expensive ligands, high catalytic loading, and poor regioselectivity. Herein, we describe the use of a cheap and easy-To-handle (cyclopentadienone)iron complex (1a), previously developed by some of us, as a precatalyst for the reductive opening of epoxides with H2. While aryl epoxides smoothly reacted to afford linear alcohols, aliphatic epoxides turned out to be particularly challenging, requiring the presence of a Lewis acid cocatalyst. Remarkably, we found that it is possible to steer the regioselectivity with a careful choice of Lewis acid. A series of deuterium labeling and computational studies were run to investigate the reaction mechanism, which seems to involve more than a single pathway.
The effects of metals and ligands on the oxidation of n-octane using iridium and rhodium “PNP” aminodiphosphine complexes
Naicker, Dunesha,Alapour, Saba,Friedrich, Holger B
, p. 282 - 289 (2020/12/01)
Ir and Rh “PNP” complexes with different ligands are utilized for the oxidation of n-octane. Based on the obtained conversion, selectivity, and the characterized recovered catalysts, it is found that the combination of Ir and the studied ligands does not promote the redox mechanism that is known to result in selective formation of oxo and peroxo compounds [desired species for C(1) activation]. Instead, they support a deeper oxidation mechanism, and thus higher selectivity for ketones and acids is obtained. In contrast, these ligands seem to tune the electron density around the Rh (in the Rh-PNP complexes), and thus result in a higher n-octane conversion and improved selectivity for the C(1) activated products, with minimized deeper oxidation, in comparison to Ir-PNP catalysts.
Ambient-pressure highly active hydrogenation of ketones and aldehydes catalyzed by a metal-ligand bifunctional iridium catalyst under base-free conditions in water
Wang, Rongzhou,Yue, Yuancheng,Qi, Jipeng,Liu, Shiyuan,Song, Ao,Zhuo, Shuping,Xing, Ling-Bao
, p. 1 - 7 (2021/05/17)
A green, efficient, and high active catalytic system for the hydrogenation of ketones and aldehydes to produce corresponding alcohols under atmospheric-pressure H2 gas and ambient temperature conditions was developed by a water-soluble metal–ligand bifunctional catalyst [Cp*Ir(2,2′-bpyO)(OH)][Na] in water without addition of a base. The catalyst exhibited high activity for the hydrogenation of ketones and aldehydes. Furthermore, it was worth noting that many readily reducible or labile functional groups in the same molecule, such as cyan, nitro, and ester groups, remained unchanged. Interestingly, the unsaturated aldehydes can be also selectively hydrogenated to give corresponding unsaturated alcohols with remaining C=C bond in good yields. In addition, this reaction could be extended to gram levels and has a large potential of wide application in future industrial.
