4654-39-1Relevant 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.
Molybdenum tricarbonyl complex functionalised with a molecular triazatriangulene platform on Au(111): Surface spectroscopic characterisation
Petersen, Finn,Lautenschl?ger, Irene,Schlimm, Alexander,Fl?ser, Benedikt M.,Jacob, Hanne,Amirbeigiarab, Reihaneh,Rusch, Talina R.,Strunskus, Thomas,Magnussen, Olaf,Tuczek, Felix
, p. 1042 - 1052 (2021/02/03)
Transition metal complexes form the basis for small molecule activation and are relevant for electrocatalysis. To combine both approaches the attachment of homogeneous catalysts to metallic surfaces is of significant interest. Towards this goal a molybdenum tricarbonyl complex supported by a tripodal phosphine ligand was covalently bound to a triazatriangulene (TATA) platform via an acetylene unit and the resulting TATA-functionalised complex was deposited on a Au(111) surface. The corresponding self-assembled monolayer was characterised with scanning tunnelling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and near-edge X-ray absorption fine structure (NEXAFS). The vibrational properties of the surface-adsorbed complexes were investigated with the help of infrared reflection absorption spectroscopy (IRRAS), and the frequency/intensity changes with respect to the bulk spectrum were analysed. A full vibrational analysis was performed with the help of DFT.
Enantioselective Copper(I)/Chiral Phosphoric Acid Catalyzed Intramolecular Amination of Allylic and Benzylic C?H Bonds
Ye, Liu,Tian, Yu,Meng, Xiang,Gu, Qiang-Shuai,Liu, Xin-Yuan
supporting information, p. 1129 - 1133 (2019/12/12)
Radical-involved enantioselective oxidative C?H bond functionalization by a hydrogen-atom transfer (HAT) process has emerged as a promising method for accessing functionally diverse enantioenriched products, while asymmetric C(sp3)?H bond amination remains a formidable challenge. To address this problem, described herein is a dual CuI/chiral phosphoric acid (CPA) catalytic system for radical-involved enantioselective intramolecular C(sp3)?H amination of not only allylic positions but also benzylic positions with broad substrate scope. The use of 4-methoxy-NHPI (NHPI=N-hydroxyphthalimide) as a stable and chemoselective HAT mediator precursor is crucial for the fulfillment of this transformation. Preliminary mechanistic studies indicate that a crucial allylic or benzylic radical intermediate resulting from a HAT process is involved.
