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Iron- and bismuth-catalyzed asymmetric Mukaiyama aldol reactions in aqueous media.
Chem Asian J. 2013 Dec; 8(12):3051-62.CA

Abstract

We have developed asymmetric Mukaiyama aldol reactions of silicon enolates with aldehydes catalyzed by chiral Fe(II) and Bi(III) complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (-78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water-compatible Lewis acids for the Mukaiyama aldol reaction, many Lewis acids were screened in combination with chiral bipyridine L1, which had previously been found to be a suitable chiral ligand in aqueous media. Three types of chiral catalysts that consisted of a Fe(II) or Bi(III) metal salt, a chiral ligand (L1), and an additive have been discovered and a wide variety of substrates (silicon enolates and aldehydes) reacted to afford the desired aldol products in high yields with high diastereo- and enantioselectivities through an appropriate selection of one of the three catalytic systems. Mechanistic studies elucidated the coordination environments around the Fe(II) and Bi(III) centers and the effect of additives on the chiral catalysis. Notably, both Brønsted acids and bases worked as efficient additives in the Fe(II) -catalyzed reactions. The assumed catalytic cycle and transition states indicated important roles of water in these efficient asymmetric Mukaiyama aldol reactions in aqueous media with the broadly applicable and versatile catalytic systems.

Authors+Show Affiliations

Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan), Fax: (+81) 3-5684-0634.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

24101589

Citation

Kitanosono, Taku, et al. "Iron- and Bismuth-catalyzed Asymmetric Mukaiyama Aldol Reactions in Aqueous Media." Chemistry, an Asian Journal, vol. 8, no. 12, 2013, pp. 3051-62.
Kitanosono T, Ollevier T, Kobayashi S. Iron- and bismuth-catalyzed asymmetric Mukaiyama aldol reactions in aqueous media. Chem Asian J. 2013;8(12):3051-62.
Kitanosono, T., Ollevier, T., & Kobayashi, S. (2013). Iron- and bismuth-catalyzed asymmetric Mukaiyama aldol reactions in aqueous media. Chemistry, an Asian Journal, 8(12), 3051-62. https://doi.org/10.1002/asia.201301149
Kitanosono T, Ollevier T, Kobayashi S. Iron- and Bismuth-catalyzed Asymmetric Mukaiyama Aldol Reactions in Aqueous Media. Chem Asian J. 2013;8(12):3051-62. PubMed PMID: 24101589.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Iron- and bismuth-catalyzed asymmetric Mukaiyama aldol reactions in aqueous media. AU - Kitanosono,Taku, AU - Ollevier,Thierry, AU - Kobayashi,Shū, Y1 - 2013/10/02/ PY - 2013/08/25/received PY - 2013/10/9/entrez PY - 2013/10/9/pubmed PY - 2013/10/9/medline KW - CC coupling KW - aldol reaction KW - asymmetric catalysis KW - bismuth KW - iron SP - 3051 EP - 62 JF - Chemistry, an Asian journal JO - Chem Asian J VL - 8 IS - 12 N2 - We have developed asymmetric Mukaiyama aldol reactions of silicon enolates with aldehydes catalyzed by chiral Fe(II) and Bi(III) complexes. Although previous reactions often required relatively harsh conditions, such as strictly anhydrous conditions, very low temperatures (-78 °C), etc., the reactions reported herein proceeded in the presence of water at 0 °C. To find appropriate chiral water-compatible Lewis acids for the Mukaiyama aldol reaction, many Lewis acids were screened in combination with chiral bipyridine L1, which had previously been found to be a suitable chiral ligand in aqueous media. Three types of chiral catalysts that consisted of a Fe(II) or Bi(III) metal salt, a chiral ligand (L1), and an additive have been discovered and a wide variety of substrates (silicon enolates and aldehydes) reacted to afford the desired aldol products in high yields with high diastereo- and enantioselectivities through an appropriate selection of one of the three catalytic systems. Mechanistic studies elucidated the coordination environments around the Fe(II) and Bi(III) centers and the effect of additives on the chiral catalysis. Notably, both Brønsted acids and bases worked as efficient additives in the Fe(II) -catalyzed reactions. The assumed catalytic cycle and transition states indicated important roles of water in these efficient asymmetric Mukaiyama aldol reactions in aqueous media with the broadly applicable and versatile catalytic systems. SN - 1861-471X UR - https://www.unboundmedicine.com/medline/citation/24101589/Iron__and_bismuth_catalyzed_asymmetric_Mukaiyama_aldol_reactions_in_aqueous_media_ L2 - https://doi.org/10.1002/asia.201301149 DB - PRIME DP - Unbound Medicine ER -
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