A Catalytic Asymmetric Strecker-Type Reaction: Interesting Reactivity Difference between TMSCN and HCN

Takamura, Masahiro; Hamashima, Yoshitaka; Usuda, Hiroyuki; Kanai, Motomu; Shibasaki, Masakatsu

doi:10.1002/(sici)1521-3773(20000502)39:9<1650::aid-anie1650>3.0.co;2-p

Cited by 203 publications

(72 citation statements)

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“…The reaction gave O-TMS cyanohydrin with 51 % ee in 48 % yield at 0°C for 30 h, but the reaction carried out at Ϫ27°C gave only trace amounts of product with 57 % ee after 38 h. Consequently, the best reaction conditions were found to involve 20 mol % of (1R,2S)-1b Ti(OiPr) 4 (1:1.2) and 0.34  acetophenone in CH 2 Cl 2 at 0°C. Table 7.…”

Section: Optimization Of the Catalystmentioning

confidence: 99%

“…A solution of methyl (S)-1-arylpyrrolidine-2-carboxylate (5) (1 mmol) in THF (10 mL) was added to the phenylmagnesium bromide solution at 0 to Ϫ10°C with ice-salt bath cooling over 1 h. After the addition, the cooling bath was removed and the reaction mixture was allowed to warm to room temperature and stirred for 1 d. Satd. NH 4 Cl was added to the reaction mixture. The resulting mixture was concentrated under reduced pressure to remove THF and the resulting aqueous mixture was extracted with diethyl ether (3 ϫ 10 mL).…”

Section: (S)-1-arylmethyl-2-(hydroxydiphenylmethyl)pyrrolidinesmentioning

confidence: 99%

“…Ti(OiPr) 4 (1  in toluene, 41 µL, 0.041 mmol) was added at room temperature to a solution of (1R,2S)-1b (12.2 mg, 0.034 mmol) in CH 2 Cl 2 (1 mL), and the mixture was stirred for 1 h. CH 2 Cl 2 was evaporated under reduced pressure and the resulting residue was further dried in vacuo for 30 min. The residue was dissolved in CH 2 Cl 2 (0.5 mL).…”

Section: General Procedures For Asymmetric Cyanosilylation Of Ketonesmentioning

confidence: 99%

“…Very recently, Shibasaki et al have reported a series of bifunctional Lewis acid/Lewis base (LALB) catalysts derived from BINOL and natural glucose as the chiral scaffold. In particular, phosphane oxide derived catalysts ( Figure 1) were very efficient for the asymmetric cyanosilylation of aldehydes, [3] imines (Strecker reaction), [4] and ketones, [5] as well as for the addition of cyanide enantiomeric excesses of up to 69 %. A catalytic cycle based on experimental phenomena and studies was proposed to explain the origin of the asymmetric induction.…”

Section: Introductionmentioning

confidence: 99%

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Asymmetric Cyanosilylation of Ketones Catalyzed by Bifunctional Chiral N‐Oxide Titanium Complex Catalysts

Shen

Feng

et al. 2003

Eur J Org Chem

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Section: Optimization Of the Catalystmentioning

confidence: 99%

Section: (S)-1-arylmethyl-2-(hydroxydiphenylmethyl)pyrrolidinesmentioning

confidence: 99%

Section: General Procedures For Asymmetric Cyanosilylation Of Ketonesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Asymmetric Cyanosilylation of Ketones Catalyzed by Bifunctional Chiral N‐Oxide Titanium Complex Catalysts

Shen

Feng

et al. 2003

Eur J Org Chem

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“…A unique and efficient catalytic asymmetric total synthesis of epothilones A and B was achieved by combining three original catalytic asymmetric reactions developed in our laboratory, clearly demonstrating the practicality and power of these catalysts for the synthesis of complex molecules. 38) The catalytic asymmetric Strecker-type reaction 39) is one of the most direct and efficient methods for the asymmetric synthesis of natural and unnatural a-amino acids. Several excellent reactions of this type were recently reported.…”

Section: -2 Application To a Catalytic Asymmetric Total Synthesis Omentioning

confidence: 99%

Multifunctional Asymmetric Catalysis.

Shibasaki

Kanai

2001

Chem. Pharm. Bull.

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Two types of general and practical enantioselective catalysts, namely, bimetallic complexes and Lewis acid-Lewis base bifunctional catalysts were developed based on the concept of multifunctional catalysis. In the first part of this review, the first example of a catalytic enatioselective nitro-Mannich reaction as well as a direct catalytic enantioselective aldol reaction of 2-hydroxyacetophenone using bimetallic complexes is discussed. The new complex, composed of ytterbium, potassium, and BINOL in a ratio of 1 : 1 : 3, promoted the nitro-Mannich reaction of nitromethane with up to 91% ee. On the other hand, second generation ALB catalyzed an enantioselective and diastereoselective nitro-Mannich reaction of nitroalkanes in up to 83% ee with a diastereomeric ratio up to 7 : 1. Moreover, the reaction of aldehydes with 2-hydroxyacetophenone in the presence of LLB, KHMDS, and H 2 O selectively gave the corresponding anti-a a,b b-dihydroxy ketones in up to 95% ee and, in the presence of the catalyst prepared from linked-BINOL and 2 eq of Et 2 Zn, selectively afforded the syn-a a,b b-dihydroxy ketones in up to 86% ee. In the second part, the development of new catalysts displaying a Lewis acidity and a Lewis basicity is described. The Lewis acid of the catalyst activates aldehydes, imines, acyl quinoliniums, and ketones. At the same time, the Lewis base activates the nucleophile (TMSCN). Catalysts of this type produced a highly enantioselective cyanation of these electrophiles. Application of the catalytic enantioselective cyanosilylation of aldehydes to a total synthesis of epothilones is also described.

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The Catalytic AsymmetricStrecker Reaction

2008

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Alpha‐amino acids are important building blocks for proteins, peptides, and pharmaceuticals. Among a variety of methods to synthesize optically active alpha‐amino acids, the Strecker reaction is one of the simplest and most powerful. This reaction consists of three steps (1) condensation of an aldehyde or ketone with an amine to produce and imine, (2) nucleophilic attack of cyanide on the imine to produce and amino nitrile, and (3) hydrolysis of the amino nitrile to the corresponding alpha‐amino acid. These steps can be conducted in one pot. Conversion of the nitrile group to amide, amine, or aldehyde functionalities is also possible. The catalytic promotion and enantiocontrol of the cyanide addition to the imines is the main focus of the Strecker reaction. Therefore, isolated and purified imines are normally used as substrates. The catalyst turnover efficiency and enantioselectivity of this step are intimately related to the electronic and steric characteristics of the substrate imines, with nitrogen substituent greatly contributing to these factors. However, since optically active alpha‐amino acids are generally the synthetic target of the catalytic asymmetric Strecker reaction, the accessibilty of the starting imines and ease of final deprotection of the product are also important considerations. This chapter focuses on catalytic enantioselective Strecker and Reissert reactions.

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A Catalytic Asymmetric Strecker-Type Reaction: Interesting Reactivity Difference between TMSCN and HCN

Cited by 203 publications

References 0 publications

Asymmetric Cyanosilylation of Ketones Catalyzed by Bifunctional Chiral N‐Oxide Titanium Complex Catalysts

Asymmetric Cyanosilylation of Ketones Catalyzed by Bifunctional Chiral N‐Oxide Titanium Complex Catalysts

Multifunctional Asymmetric Catalysis.

The Catalytic AsymmetricStrecker Reaction

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