The Implications of the Brønsted Acidic Properties of Crabtree-Type Catalysts in the Asymmetric Hydrogenation of Olefins

Peters, Bram B. C.; Andersson, Pher G.

doi:10.1021/jacs.2c07023

Cited by 16 publications

(4 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The dominant product in this reaction ( 2 d ) was generated through cleavage of the alcohol moiety, leaving the tetrasubstituted olefin untouched. Iridium‐based hydrogenation catalysts have been shown to form Brønsted‐acidic intermediates as part of the catalytic cycle, which can cause the formation of undesired side products in acid‐sensitive substrates [3i,11] . Allylic alcohols like compound 1 are frequently susceptible to acid‐catalyzed elimination and subsequent hydrogenation of the more accessible olefin [12]…”

Section: Resultsmentioning

confidence: 99%

Diastereoselective Hydrogenation of Tetrasubstituted Olefins using a Heterogeneous Pt‐Ni Alloy Catalyst

Swann,

Yadav,

Colvin

et al. 2024

Angewandte Chemie

View full text Add to dashboard Cite

Stereoselective hydrogenation of tetrasubstituted olefins is an attractive method to access compounds with two contiguous stereocenters. However, homogeneous catalysts for enantio‐ and diastereostereoselective hydrogenation exhibit low reactivity toward tetrasubstituted olefins due to steric crowding between the ligand scaffold and the substrate. Monometallic heterogeneous catalysts, on the other hand, provide accessible surface active sites for hindered olefins but exhibit unpredictable and inconsistent stereoinduction. In this work, we develop a Pt‐Ni bimetallic alloy catalyst that can diastereoselectively hydrogenate unactivated, sterically‐bulky tetrasubstituted olefins, utilizing the more oxophilic Ni atoms to adsorb a hydroxyl directing group and direct facially‐selective hydrogen addition to the olefin via the Pt atoms. Structure‐activity studies on several Pt‐Ni compositions underscore the importance of exposing a uniform PtNi alloy surface to achieve high diastereoselectivity and minimize side reactions. The optimized Pt‐Ni/SiO2 catalyst exhibits good functional group tolerance and broad scope for tetrasubstituted olefins in a cyclopentene scaffold, generating cyclopentanol products with three contiguous stereocenters. The synthetic utility of the method is demonstrated in a four‐step synthesis of (1R, 2S)‐(+)‐cis‐methyldihydrojasmonate with high yield and enantiopurity.

show abstract

Section: Resultsmentioning

confidence: 99%

Diastereoselective Hydrogenation of Tetrasubstituted Olefins using a Heterogeneous Pt‐Ni Alloy Catalyst

Swann,

Yadav,

Colvin

et al. 2024

Angewandte Chemie

View full text Add to dashboard Cite

show abstract

“…Bidentate (mixed donor) chiral ligands developed by Pfaltz et al [58] and Andersson et al [59] are mostly used in Ir-catalyzed asymmetric hydrogenation of olefins. On the other hand, the use of chiral monodentate phosphines in Ir-catalyzed enantioselective hydrogenation is uncommon.…”

Section: Catalysismentioning

confidence: 99%

Access to Enantiomerically Pure P-Chiral 1-Phosphanorbornane Silyl Ethers

Ramazanova,

Chakrabortty,

Kallmeier

et al. 2023

Molecules

View full text Add to dashboard Cite

Sulfur-protected enantiopure P-chiral 1-phosphanorbornane silyl ethers 5a,b are obtained in high yields via the reaction of the hydroxy group of P-chiral 1-phosphanorbornane alcohol 4 with tert-butyldimethylsilyl chloride (TBDMSCl) and triphenylsilyl chloride (TPSCl). The corresponding optically pure silyl ethers 5a,b are purified via crystallization and fully structurally characterized. Desulfurization with excess Raney nickel gives access to bulky monodentate enantiopure phosphorus(III) 1-phosphanorbornane silyl ethers 6a,b which are subsequently applied as ligands in iridium-catalyzed asymmetric hydrogenation of a prochiral ketone and enamide. Better activity and selectivity were observed in the latter case.

show abstract

“…However, quaternary alcohols are for obvious reasons not directly accessible via asymmetric hydrogenation. Iridium-hydride complexes are considered as potential Lewis acids and/or Brønsted acids in certain cases . In 2010, Burgess reported that many N,P-based Ir-complexes have a Brønsted acidity similar to acetic acid .…”

Section: Introductionmentioning

confidence: 99%

Iridium-Catalyzed Double Convergent 1,3-Rearrangement/Hydrogenation of Allylic Alcohols

Yang

Massaro

et al. 2022

J. Am. Chem. Soc.

Self Cite

View full text Add to dashboard Cite

Enantioconvergent catalysis has the potential to convert different isomers of a starting material to a single highly enantioenriched product. Here we report a novel enantioselective double convergent 1,3-rearrangement/hydrogenation of allylic alcohols using an Ir-N,P catalyst. A variety of allylic alcohols, each consisting of a 1:1:1:1 mixture of four isomers, were converted to the corresponding tertiary alcohols with two contiguous stereogenic centers, in up to 99% ee and 99:1 d.r. DFT calculations, and control experiments suggest that the 1,3-rearrangement is the crucial stereodetermining element of the reaction.

show abstract

The Implications of the Brønsted Acidic Properties of Crabtree-Type Catalysts in the Asymmetric Hydrogenation of Olefins

Cited by 16 publications

References 84 publications

Diastereoselective Hydrogenation of Tetrasubstituted Olefins using a Heterogeneous Pt‐Ni Alloy Catalyst

Diastereoselective Hydrogenation of Tetrasubstituted Olefins using a Heterogeneous Pt‐Ni Alloy Catalyst

Access to Enantiomerically Pure P-Chiral 1-Phosphanorbornane Silyl Ethers

Iridium-Catalyzed Double Convergent 1,3-Rearrangement/Hydrogenation of Allylic Alcohols

Contact Info

Product

Resources

About