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Asymmetric hydrogenation using monodentate phosphoramidite ligands.
Acc Chem Res. 2007 Dec; 40(12):1267-77.AC

Abstract

Monodentate phosphoramidites are excellent ligands for Rh-catalyzed asymmetric hydrogenations of substituted olefins. Enantioselectivities between 95 and 99% were obtained in the asymmetric hydrogenation of protected alpha- and beta-dehydroamino acids and esters, itaconic acid and esters, aromatic enamides, aromatic enol esters, aromatic and aliphatic enol carbamates, and alpha-substituted cinnamic acids. An iridium catalyst Ir(L*)(COD)Cl was developed that contains only a single bulky phosphoramidite based on 3,3'-disubstituted BINOL or bisphenol as a chiral ligand. With this catalyst, acetylated dehydroamino acid esters could be hydrogenated with very good enantioselectivity. Most reactions have turnover frequencies of 250-1600 h (-1), depending upon the hydrogen pressure. The enantioselectivity is unaffected by the pressure over a wide range. Because of their modularity and easy synthesis, parallel ligand synthesis is possible. Results obtained with these library ligands deviate only slightly from those obtained with purified ligands. Using this instant ligand library protocol, DSM has developed catalysts for industrial processes. These MonoPhos ligands are currently used in production for pharmaceutical intermediates by DSM. It is possible to use catalysts based on a mixture of two different monodentate ligands, such as two different monodentate phosphoramidites or one phosphoramidite and one achiral phosphine ligand. Dependent upon the substrate, the "mixed" catalyst may lead to higher enantioselectivity and rate than the "homocatalysts".

Authors+Show Affiliations

Organic and Molecular Inorganic Chemistry, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

17705446

Citation

Minnaard, Adriaan J., et al. "Asymmetric Hydrogenation Using Monodentate Phosphoramidite Ligands." Accounts of Chemical Research, vol. 40, no. 12, 2007, pp. 1267-77.
Minnaard AJ, Feringa BL, Lefort L, et al. Asymmetric hydrogenation using monodentate phosphoramidite ligands. Acc Chem Res. 2007;40(12):1267-77.
Minnaard, A. J., Feringa, B. L., Lefort, L., & de Vries, J. G. (2007). Asymmetric hydrogenation using monodentate phosphoramidite ligands. Accounts of Chemical Research, 40(12), 1267-77.
Minnaard AJ, et al. Asymmetric Hydrogenation Using Monodentate Phosphoramidite Ligands. Acc Chem Res. 2007;40(12):1267-77. PubMed PMID: 17705446.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Asymmetric hydrogenation using monodentate phosphoramidite ligands. AU - Minnaard,Adriaan J, AU - Feringa,Ben L, AU - Lefort,Laurent, AU - de Vries,Johannes G, Y1 - 2007/08/18/ PY - 2007/8/21/pubmed PY - 2008/3/7/medline PY - 2007/8/21/entrez SP - 1267 EP - 77 JF - Accounts of chemical research JO - Acc Chem Res VL - 40 IS - 12 N2 - Monodentate phosphoramidites are excellent ligands for Rh-catalyzed asymmetric hydrogenations of substituted olefins. Enantioselectivities between 95 and 99% were obtained in the asymmetric hydrogenation of protected alpha- and beta-dehydroamino acids and esters, itaconic acid and esters, aromatic enamides, aromatic enol esters, aromatic and aliphatic enol carbamates, and alpha-substituted cinnamic acids. An iridium catalyst Ir(L*)(COD)Cl was developed that contains only a single bulky phosphoramidite based on 3,3'-disubstituted BINOL or bisphenol as a chiral ligand. With this catalyst, acetylated dehydroamino acid esters could be hydrogenated with very good enantioselectivity. Most reactions have turnover frequencies of 250-1600 h (-1), depending upon the hydrogen pressure. The enantioselectivity is unaffected by the pressure over a wide range. Because of their modularity and easy synthesis, parallel ligand synthesis is possible. Results obtained with these library ligands deviate only slightly from those obtained with purified ligands. Using this instant ligand library protocol, DSM has developed catalysts for industrial processes. These MonoPhos ligands are currently used in production for pharmaceutical intermediates by DSM. It is possible to use catalysts based on a mixture of two different monodentate ligands, such as two different monodentate phosphoramidites or one phosphoramidite and one achiral phosphine ligand. Dependent upon the substrate, the "mixed" catalyst may lead to higher enantioselectivity and rate than the "homocatalysts". SN - 0001-4842 UR - https://www.unboundmedicine.com/medline/citation/17705446/Asymmetric_hydrogenation_using_monodentate_phosphoramidite_ligands_ L2 - https://doi.org/10.1021/ar7001107 DB - PRIME DP - Unbound Medicine ER -