Catalytic asymmetric induction.  Highly enantioselective addition of dialkylzincs to aldehydes

Kitamura, Masato; Suga, Seiji; Kawai, Koji; Noyori, Ryoji

doi:10.1021/ja00279a083

Cited by 568 publications

(189 citation statements)

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“…However, their application to enantioselective reactions was somewhat limited in the early stage, because thioureas are weaker acids than metallic Lewis acids. In 2003, we first introduced a chiral bifunctional thiourea bearing a tertiary amino group, 74,75) by which a wide range of asymmetric reactions were dramatically promoted with high enantioselectivity on the basis of the dual-activation protocol [76][77][78][79][80] of electrophile and nucleophile. In this review, we provide a comprehensive overview of our recent studies on bifunctional thiourea-mediated asymmetric nucleophilic reactions.…”

Section: Introductionmentioning

confidence: 99%

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

Takemoto

2010

CHEMICAL & PHARMACEUTICAL BULLETIN

395

107

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We have developed several multifunctional thiourea catalysts bearing a tertiary amine or an 1,2-amino alcohol in expectation of their synchronous activation of a nucleophile and an electrophile through both acid-base and hydrogen-bonding interactions. From these studies, it was revealed that the weak acidity of thioureas compared with metallic Lewis acids could be overcome by this modification. The bifunctional aminothiourea could be used efficiently for a wide range of diastereoselective and enantioselective nucleophilic reactions such as Michael addition of 1,3-dicarbonyl compounds to nitroolefines, aza-Henry reaction of nitroalkanes to N-Boc imines, and hydrazination of cyclic b b-keto esters. We also discovered that multifunctional thiourea catalyst, bearing an 1,2-amino alcohol moiety, significantly accelerated the Petasis-type reaction of alkenylboronic acids to Nphenoxycarbonyl quinolinium salts, prepared from quinolines and phenyl chloroformate, to afford 1,2-addition products with high enantioselectivity (up to 97% ee). Furthermore, to expand the synthetic applicability of the thiourea-catalyzed asymmetric reactions, tandem organocatalyzed reactions were explored to establish the concise one-pot synthesis of chiral densely functionalized three-, five-, and six-membered compounds.

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Section: Introductionmentioning

confidence: 99%

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

Takemoto

2010

CHEMICAL & PHARMACEUTICAL BULLETIN

395

107

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“…The only previous results in the catalytic asymmetric phenylation of ketones were reported by Dosa and Fu in 1998 (11). In this pioneering work, these authors used Noyori's amino alcohol ligand, (ϩ)-3-exo-(dimethylamino)isoborneol [(ϩ)-DAIB] (12,13), and diphenylzinc (3.5 eq). Initially, the reaction gave low yields and moderate enantioselectivities.…”

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confidence: 99%

Catalytic asymmetric addition of diphenylzinc to cyclic α,β-unsaturated ketones

García

Walsh

2004

Proc. Natl. Acad. Sci. U.S.A.

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We have examined the use of our bis(sulfonamide) diol ligand (1) in the asymmetric addition of phenyl groups to cyclic ␣,␤-unsaturated ketones. Good to excellent enantioselectivities have been obtained with cyclic enones bearing alkyl substituents in the 2 position (71-97% enantiomeric excess). Furthermore, excellent enantioselectivities have been observed in the asymmetric phenylation of cyclic enones with 2-iodo and 2-bromo substituents. The results of this study broaden the scope of the asymmetric additions to ketones promoted by the titanium catalyst derived from ligand 1.alkylation ͉ tertiary alcohols ͉ zinc ͉ titanium ͉ asymmetric catalysis W e recently developed a highly enantioselective titanium catalyst based on the bis(sulfonamide) diol ligand 1 (Fig. 1) for the asymmetric addition of alkylzinc reagents to ketones (Eq. 1; ref. 1). When cyclic ␣,␤-unsaturated ketones were used as substrates, we found that the asymmetric addition reaction could be coupled with a diastereoselective epoxidation by using molecular oxygen as the oxidant to provide a one-pot synthesis of epoxy alcohols with high enantio-and diastereoselectivity (Eq. 2; ref. 2). These studies provide a solution to a long-standing problem in synthetic organic chemistry: the catalytic synthesis of tertiary alcohols from ketones with high enantioselectivity. Unlike related additions of dialkylzinc reagents to aldehyde substrates, which are promoted by hundreds of catalysts (3, 4), only a few systems will catalyze alkyl additions to ketones (1, 2, 5-8), and most of them use high catalyst loadings and long reaction times (6-8).The successful use of ligand 1 in the alkyl additions to ketones led our group (9) and Yus and coworkers (10) to examine the enantioselective phenylation of acyclic ketones with ZnPh 2 . The only previous results in the catalytic asymmetric phenylation of ketones were reported by Dosa and Fu in 1998 (11). In this pioneering work, these authors used Noyori's amino alcohol ligand, (ϩ)-3-exo-(dimethylamino)isoborneol [(ϩ)-DAIB] (12, 13), and diphenylzinc (3.5 eq). Initially, the reaction gave low yields and moderate enantioselectivities. It was found, however, that addition of 1.5 eq of methanol to the diphenylzinc resulted in formation of a mixed alkoxy phenyl zinc reagent that led to increased yields and enantioselectivities (Eq. 3) (11). Under these conditions, excellent enantioselectivities were obtained with substituted propiophenones [86-91% enantiomeric excess (ee)], and acetophenone derivatives afforded enantioselectivities as high as 80%. In the case of cyclohexyl methyl ketone and 3-methyl-2-butanone, the reaction proceeded with 75% and 60% enantioselectivities, respectively. Yields in the phenylation reaction with DAIB ranged from 53% to 91%. In contrast to the phenylation of ketones, several highly enantioselective catalysts have been developed for the asymmetric addition of phenyl groups to aldehydes (14-20).In our initial study on the addition of diphenylzinc to acyclic ketones with ligand 1, we found that enantio...

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“…11,12 Also various camphor based P,Nligands (III) were used in asymmetric hydrogenations. 13,14 Additionally, some of the camphor derivatives show interesting biological activities.…”

Section: -10mentioning

confidence: 99%

One-pot, Three-component Synthesis of Fully Substituted 1,3,4-Oxadiazole Derivatives from (N-Isocyanoimino)triphenylphosphorane, Aromatic Carboxylic acids and (1R)-(-)-Campherchinon

Ramazani¹,

Nasrabadi²,

Abdian³

et al. 2012

Bulletin of the Korean Chemical Society

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Catalytic asymmetric induction. Highly enantioselective addition of dialkylzincs to aldehydes

Cited by 568 publications

References 1 publication

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

Development of Chiral Thiourea Catalysts and Its Application to Asymmetric Catalytic Reactions

Catalytic asymmetric addition of diphenylzinc to cyclic α,β-unsaturated ketones

One-pot, Three-component Synthesis of Fully Substituted 1,3,4-Oxadiazole Derivatives from (N-Isocyanoimino)triphenylphosphorane, Aromatic Carboxylic acids and (1R)-(-)-Campherchinon

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