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1. Cobalt‐Catalyzed Aerobic Oxidative Cleavage of Alkyl Aldehydes: Synthesis of Ketones, Esters, Amides, and α‐Ketoamides

   https://doi.org/10.1002/chem.202101035  

   Li, Tingting; Hammond, Gerald_B; Xu, Bo (May 2021, Chemistry – A European Journal)

   Abstract A widely applicable approach was developed to synthesize ketones, esters, amides via the oxidative C−C bond cleavage of readily available alkyl aldehydes. Green and abundant molecular oxygen (O₂) was used as the oxidant, and base metals (cobalt and copper) were used as the catalysts. This strategy can be extended to the one‐pot synthesis of ketones from primary alcohols and α‐ketoamides from aldehydes. 

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2. Diplumbane-catalysed solvent- and additive-free hydroboration of ketones and aldehydes

   https://doi.org/10.1039/D2RA03731A  

   Zhang, Guoqi; Li, Sihan; Zeng, Haisu; Zheng, Shengping; Neary, Michelle C. (June 2022, RSC Advances)

   A new diplumbane, namely [Pb(CH 2 SiMe 3 ) 3 ] 2 , was synthesized and structurally characterized. This group 14 element compound was found to catalyse the hydroboration of ketones and aldehydes under mild conditions without the use of additives and solvents, leading to the synthesis of a range of alcohols in high yields after hydrolysis. 

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3. Homogeneous versus MOF-supported catalysis: A direct comparison of catalytic hydroboration at Ni tripodal P ₃ E (E = Si, Ge) complexes

   https://doi.org/10.1039/D3DT01328F  

   Barrios-Vargas, Luz Jimena; Abeynayake, Niroshani Samitri; Secrist, Carlee; Le, Nghia; Webster, Charles Edwin; Donnadieu, Bruno; Kaphan, David M; Roy, Amitava; Ibarra, Ilich A.; Montiel-Palma, Virginia (January 2023, Dalton Transactions)

   MOF NU-1000 was employed to host Ni tripodal complexes prepared from new organometallic precursors [HNi(κ4(E,P,P,P)-E(o-C 6 H 4 CH 2 PPh 2 ) 3 ], E = Si (Ni-1), Ge (Ni-2). The new heterogenous catalytic materials, Ni-1@NU-1000 and Ni-2@NU-1000 show the advantages of both homogenous and heterogeneous catalysts. They catalyze the hydroboration of aldehydes and ketones more efficiently than the homogenous Ni-1 and Ni-2, under aerobic conditions, and allowing recyclability of the catalyst. 

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4. 1-D manganese( ii )-terpyridine coordination polymers as precatalysts for hydrofunctionalisation of carbonyl compounds

   https://doi.org/10.1039/c9dt04637b  

   Zhang, Guoqi; Zeng, Haisu; Li, Sihan; Johnson, Jahvon; Mo, Zixuan; Neary, Michelle C.; Zheng, Shengping (February 2020, Dalton Transactions)

   Reductive catalysis with earth-abundant metals is currently of increasing importance and shows potential in replacing precious metal catalysis. In this work, we revealed catalytic hydroboration and hydrosilylation of ketones and aldehydes achieved by a structurally defined manganese( ii ) coordination polymer (CP) as a precatalyst under mild conditions. The manganese-catalysed methodology can be applied to a range of functionalized aldehydes and ketones with turnover numbers (TON) of up to 990. Preliminary results on the regioselective catalytic hydrofunctionalization of styrenes by the Mn-CP catalyst are also presented. 

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5. Light-mediated aerobic oxidation of C(sp ³ )–H bonds by a Ce( iv ) hexachloride complex

   https://doi.org/10.1039/D2QO00362G  

   Wang, Yu-Heng; Yang, Qiaomu; Walsh, Patrick J.; Schelter, Eric J. (May 2022, Organic Chemistry Frontiers)

   A photochemical C(sp 3 )–H oxygenation of alkane and arene substrates catalyzed by [NEt 4 ] 2 [Ce IV Cl 6 ] under mild conditions (1 atm, 25 °C) is described. Time-course studies reveal that the hydrocarbons are oxidized in a stepwise fashion to afford alcohols, aldehydes, ketones, and carboxylic acids. The catalyst resting state, [Ce IV Cl 6 ] 2− , is observed by UV-visible spectroscopy. On/off light-switching experiments, quantum yield measurements, and the absence of a kinetic isotope effect on parallel C–H/C–D functionalization suggest that ligand-to-metal charge transfer of [NEt 4 ] 2 [Ce IV Cl 6 ] to generate Cl˙ is the turnover-limiting step. The involvement of a highly reducing excited-state [NEt 4 ] 3 [Ce III Cl 6 ]* species as well as photo-excited aldehyde, under black light irradiation appears to facilitate the conversion of primary alcohols and aldehydes to carboxylic acids. Remarkably, this approach is found to be capable of direct activation of light alkanes, including methane and ethane. 

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