More Like this

1. Manganese Salan Complexes as Catalysts for Hydrosilylation of Aldehydes and Ketones

   https://doi.org/10.3390/catal13040665  

   Almutairi, Nora; Vijjamarri, Srikanth; Du, Guodong (April 2023, Catalysts)

   Manganese has attracted significant recent attention due to its abundance, low toxicity, and versatility in catalysis. In the present study, a series of manganese (III) complexes supported by salan ligands have been synthesized and characterized, and their activity as catalysts in the hydrosilylation of carbonyl compounds was examined. While manganese (III) chloride complexes exhibited minimal catalytic efficacy without activation of silver perchlorate, manganese (III) azide complexes showed good activity in the hydrosilylation of carbonyl compounds. Under optimized reaction conditions, several types of aldehydes and ketones could be reduced with good yields and tolerance to a variety of functional groups. The possible mechanisms of silane activation and hydrosilylation were discussed in light of relevant experimental observations. 

   more » « less
2. Ir( iii )-catalyzed ortho C–H alkylations of (hetero)aromatic aldehydes using alkyl boron reagents

   https://doi.org/10.1039/C8SC03606C  

   Chen, Xiao-Yang; Sorensen, Erik J. (December 2018, Chemical Science)

   Transition-metal-catalyzed C–H alkylation reactions directed by aldehydes or ketones have been largely restricted to electronically activated alkenes. Herein, we report a general protocol for the Ir( iii )-catalyzed ortho C–H alkylations of (hetero)aromatic aldehydes using alkyl boron reagents as the coupling partner. Featuring aniline as an inexpensive catalytic ligand, the method was compatible with a wide variety of benzaldehydes, heterocyclic aldehydes, potassium alkyltrifluoroborates as well as a few α,β-unsaturated aldehydes. An X-ray crystal structure of a benzaldehyde ortho C–H iridation intermediate was also successfully obtained. 

   more » « less
3. Palladium Nano-Dispersed and Stabilized in Organically Modified Silicate as a Heterogeneous Catalyst for the Conversion of Aldehydes into O-Silyl Ether Derivatives under Neat Conditions

   https://doi.org/10.1055/a-2326-6277  

   Matherne, Caitlyn M; Wroblewski, Jordan E; Drago, Heather S; Marchan, Gabriela T; Young, Alexis R; Kingsley, Nkechi; Plaisance, Craig P; Fotie, Jean (June 2024, Synthesis)

   Abstract Palladium nanoparticles are dispersed and stabilized in organically modified silicate (Pd@MTES), and characterized by a number of spectroscopic techniques, including FTIR, TEM, SEM, and XPS. The catalytic effect of this material toward the hydrosilylation of aldehydes and ketones is explored, and the scope of the reaction investigated, with 26 examples provided. This reaction proceeds under neat conditions via heterogeneous catalysis, and a mechanistic pathway supported by DFT calculations is proposed. 

   more » « less
4. Diastereodivergent synthesis of 4-oxocyclohexanecarbaldehydes by using the modularly designed organocatalysts upon switching on their iminium catalysis

   https://doi.org/10.1039/D1CC01020D  

   Bora, P.; Jakkampudi, S.; Parella, R.; Sakkani, N.; Dai, Q.; Bihani, M.; Arman, H. D.; Zhao, J. C.-G. (January 2021, Chemical communications)

   null (Ed.)

   The cinchona thiourea moiety in the self-assembled modularly designed organocatalysts (MDOs) switches off the iminium catalysis of these catalysts. In this study, it was found that the inhibited iminium catalysis could be switched on by using an appropriate weak acid and that, once the iminium catalysis was switched on, these catalysts could be applied for the highly stereoselective and diastereodivergent synthesis of 4-oxocyclohexanecarbaldehydes via a domino reaction between ketones and α,β-unsaturated aldehydes. 

   more » « less
5. Generation and Stabilization of a Dinickel Catalyst in a Metal‐Organic Framework for Selective Hydrogenation Reactions

   https://doi.org/10.1002/anie.202306905  

   Guo, Qing‐Yun; Wang, Zitong; Feng, Xuanyu; Fan, Yingjie; Lin, Wenbin (July 2023, Angewandte Chemie International Edition)

   Abstract Although many monometallic active sites have been installed in metal–organic frameworks (MOFs) for catalytic reactions, there are no effective strategies to generate bimetallic catalysts in MOFs. Here we report the synthesis of a robust, efficient, and reusable MOF catalyst, MOF‐NiH, by adaptively generating and stabilizing dinickel active sites using the bipyridine groups in MOF‐253 with the formula of Al(OH)(2,2′‐bipyridine‐5,5′‐dicarboxylate) forZ‐selective semihydrogenation of alkynes and selective hydrogenation of C=C bonds in α,β‐unsaturated aldehydes and ketones. Spectroscopic studies established the dinickel complex (bpy⋅⁻)Ni^II(μ₂‐H)₂Ni^II(bpy⋅⁻) as the active catalyst. MOF‐NiH efficiently catalyzed selective hydrogenation reactions with turnover numbers of up to 192 and could be used in five cycles of hydrogenation reactions without catalyst leaching or significant decrease of catalytic activities. The present work uncovers a synthetic strategy toward solution‐inaccessible Earth‐abundant bimetallic MOF catalysts for sustainable catalysis. 

   more » « less