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[Acid-base catalysis of chiral Pd complexes: development of novel asymmetric reactions].
Yakugaku Zasshi. 2005 Oct; 125(10):785-93.YZ

Abstract

Using a unique character of the chiral palladium complexes 1 and 2, several types of novel catalytic asymmetric reactions have been developed. In contrast to the conventional Pd(0)-catalyzed reactions, these complexes function as an acid-base catalyst. Thus active methine compounds were activated to form chiral palladium enolates, which underwent the enantioselective Michael reaction and Mannich-type reaction with up to 99% ee. Interestingly, these palladium enolates acted cooperatively with a strong protic acid activating the electrophiles, formed concomitantly during the formation of the enolates, whereby the C-C bond-forming reaction was promoted. In addition, this palladium enolate chemistry was also applicable to the electrophilic asymmetric fluorination reactions, and thus various carbonyl compounds including beta-ketoesters, beta-ketophosphonates, and oxindoles were fluorinated in a highly enantioselective manner (up to 98% ee). It is advantageous that these reactions were carried out in environmentally friendly alcoholic solvents such as ethanol, and exclusion of air and moisture is not necessary.

Authors+Show Affiliations

Hamashima Y
Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, Japan. yhamashi@tagen.tohoku.ac.jp

MeSH

AcidsCatalysisChemistry, OrganicEstersEthanolFluorineIndolesOrganic Chemistry PhenomenaOrganometallic CompoundsPalladiumSolventsStereoisomerism

Pub Type(s)

English Abstract
Journal Article
Research Support, Non-U.S. Gov't
Review

Language

jpn

PubMed ID

16205036

Citation

Hamashima, Yoshitaka. "[Acid-base Catalysis of Chiral Pd Complexes: Development of Novel Asymmetric Reactions]." Yakugaku Zasshi : Journal of the Pharmaceutical Society of Japan, vol. 125, no. 10, 2005, pp. 785-93.
Hamashima Y. [Acid-base catalysis of chiral Pd complexes: development of novel asymmetric reactions]. Yakugaku Zasshi. 2005;125(10):785-93.
Hamashima, Y. (2005). [Acid-base catalysis of chiral Pd complexes: development of novel asymmetric reactions]. Yakugaku Zasshi : Journal of the Pharmaceutical Society of Japan, 125(10), 785-93.
Hamashima Y. [Acid-base Catalysis of Chiral Pd Complexes: Development of Novel Asymmetric Reactions]. Yakugaku Zasshi. 2005;125(10):785-93. PubMed PMID: 16205036.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [Acid-base catalysis of chiral Pd complexes: development of novel asymmetric reactions]. A1 - Hamashima,Yoshitaka, PY - 2005/10/6/pubmed PY - 2006/1/4/medline PY - 2005/10/6/entrez SP - 785 EP - 93 JF - Yakugaku zasshi : Journal of the Pharmaceutical Society of Japan JO - Yakugaku Zasshi VL - 125 IS - 10 N2 - Using a unique character of the chiral palladium complexes 1 and 2, several types of novel catalytic asymmetric reactions have been developed. In contrast to the conventional Pd(0)-catalyzed reactions, these complexes function as an acid-base catalyst. Thus active methine compounds were activated to form chiral palladium enolates, which underwent the enantioselective Michael reaction and Mannich-type reaction with up to 99% ee. Interestingly, these palladium enolates acted cooperatively with a strong protic acid activating the electrophiles, formed concomitantly during the formation of the enolates, whereby the C-C bond-forming reaction was promoted. In addition, this palladium enolate chemistry was also applicable to the electrophilic asymmetric fluorination reactions, and thus various carbonyl compounds including beta-ketoesters, beta-ketophosphonates, and oxindoles were fluorinated in a highly enantioselective manner (up to 98% ee). It is advantageous that these reactions were carried out in environmentally friendly alcoholic solvents such as ethanol, and exclusion of air and moisture is not necessary. SN - 0031-6903 UR - https://www.unboundmedicine.com/medline/citation/16205036/[Acid_base_catalysis_of_chiral_Pd_complexes:_development_of_novel_asymmetric_reactions]_ DB - PRIME DP - Unbound Medicine ER -