Application of enantiopure templated azomethine ylids to β-hydroxy-α-amino acid synthesis

Alker, David; Hamblett, Giles; Harwood, Laurence M.; Robertson, Sarah M.; Watkin, David J.; Williams, C.

doi:10.1016/s0040-4020(98)00302-0

Cited by 40 publications

(24 citation statements)

References 22 publications

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“…After being stirred at room temperature for 2 h, the reaction mixture was diluted with CH 2 Cl 2 and washed with H 2 O. The organic phase was dried over Na 2 Ethyl 2-Chloro-4,4-dimethyl-2-oxazolidinecarboxylate (9) To a stirred solution of 2-amino-2-methylpropanol 8 (8.94 g, 0.1 mol) and Et 3 N (18 ml, 0.13 mol) in CH 2 Cl 2 (100 ml) was added a solution of ethyl oxalyl chloride 5a (13.6 g, 0.1 mol) in CH 2 Cl 2 (50 ml) under a nitrogen atmosphere at room temperature. After the solution was stirred at the same temperature for 5 h, the reaction mixture was diluted with CH 2 Cl 2 and washed with H 2 O.…”

Section: Methodsmentioning

confidence: 99%

“…After being stirred at room temperature for 20 min, a solution of the hydroximoyl bromide 7a-c (16 mmol) in THF (80 ml) was added to reaction mixture at room temperature. After being stirred at the same temperature for 4 h, the reaction mixture was cooled at 0°C, diluted with H 2 General Procedure for Imino 1,2-Wittig Rearrangement A solution of Z-hydroximate 1a-c (1 mmol) in THF (5 ml) was added with stirring at temperature shown in Table 1 to a LDA solution, prepared from diisopropylamine (2 mmol or 4 mmol) and n-BuLi (1.65 M in hexane) (2 mmol or 4 mmol) under nitrogen atmosphere. After being stirred at the same temperature for 1 or 2 h, the reaction mixture was diluted with saturated aqueous NH 4 Cl and extracted with CH 2 Cl 2 .…”

Section: Preparation Of Hydroximates 1a-cmentioning

confidence: 99%

“…The organic phase was washed with H 2 O, dried over Na 2 SO 4 , and concentrated at reduced pressure to afford the crude amino alcohols 12 (threo : erythroϭϾ99 : Ͻ1). To a solution of the crude amino alcohols in MeCN (20 ml) were added DMAP (190 mg, 1.3 mmol) and (Boc) 2 O (672 mg, 2.86 mmol) at room temperature. After being stirred at the same temperature for 1 h, the reaction mixture was concentrated at reduced pressure.…”

Section: Preparation Of Hydroximates 1a-cmentioning

confidence: 99%

“…The organic phase was washed with H 2 O, dried over Na 2 SO 4 , and concentrated at reduced pressure to afford the crude trans-carboxylic acid. To a solution of the crude trans-carboxylic acid in MeOH (20 ml) was added a solution of CH 2 N 2 (2.1 mmol) in Et 2 O, prepared according to a usual method, at 0°C. After being stirred at the same temperature for 1 h, the reaction mixture was concentrated at reduced pressure.…”

Section: Preparation Of Hydroximates 1a-cmentioning

confidence: 99%

“…According to our previous studies, 11) the treatment of 2b with SMEAH followed by acylation of the resulting threo-amino alcohol 12 with 2.2 eq. of (Boc) 2 O gave the trans-13 with excellent stereoselectivity (entry 1). Interestingly, the reduction of silyl ether 11, prepared from 2b, with LiAlH 4 gave cis-13 via erythro-amino alcohol 12 with high stereoselectivity (entry 2).…”

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Stereoselective Synthesis of .BETA.-Hydroxyphenylalanines Using Imino 1,2-Wittig Rearrangement of Hydroximates

Miyata

Asai

Naito

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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b-Hydroxy-a-amino acids are an important class of amino acids that are found in nature and as constituents of more complex natural products. 1-7) For example, b-hydroxytyrosine and b-hydroxyphenylalanine derivatives are found in clinically important glycopeptide antibiotics, such as Vancomycin and Teicoplanin. In addition, Lysobactin, which has shown antibiotic activity, contains five b-hydroxy-a-amino acids unit in the molecule. These densely functionalized amino acids are also useful building blocks for synthesis of b-lactams and sugars. Therefore, the synthesis of polypeptides and antibiotics containing b-hydroxy-a-amino acids are of interest to both synthetic and medicinal chemists. In recent years, we have developed a new imino 1,2-Wittig rearrangement of hydroximates which proceeds smoothly under basic conditions to give 2-hydroxyoxime ethers. [8][9][10][11] Part of the synthetic potentiality was demonstrated by the preparation of biologically important amino alcohols and the efficient synthesis of Cytoxazone. 11) In this paper, we disclose a new convenient methodology for the preparation of b-hydroxy-a-amino acids using imino 1,2-Wittig rearrangement of hydroximates. Our approach is shown in Chart 1. We chose the hydroximates 1a-c having ester, furan, and oxazoline moieties as substrates for imino 1,2-Wittig rearrangement. These functional groups are expected to readily convert into a carboxyl group. The hydroximates 1a-c are treated with LDA to give 2-hydroxyoxime ethers 2 which are subjected to stereoselective reduction of imine moiety to afford both the threo-and erythro-amino alcohols 3. Finally, the conversion of ester, furan, and oxazoline moieties into a carboxylic acid gives b-hydroxy-aamino acids 4. Results and DiscussionAt first, we examined the preparation of the Z-hydroximates 1a-c (Chart 2). According to the known procedure, 11-15) the acylation of methoxyamine hydrochloride with acid chloride 5a followed by treatment of the resulting amide 6a with carbon tetrabromide in the presence of triphenyl phosphine gave imidoyl bromides 7a which was then converted into hydroximate 1a by the treatment of sodium benzyloxide. Similarly, 1b was prepared by the bromination of 6b followed by the treatment of the resulting imidoyl bromide 7b with sodium benzyloxide. The hydroximate 1c was prepared from amino alcohol 8 16,17) via construction of oxazolidine ring, amidation, bromination, and benzyloxylation.Next, we investigated the 1,2-Wittig rearrangement reaction of hydroximates 1a-c with LDA (Chart 3, Table 1). Upon treatment with 4 eq. of LDA, the rearrangement of hydroximate 1b carrying furan ring proceeded smoothly at The imino 1,2-Wittig rearrangement of hydroximates containing a furan ring provides a novel method for the synthesis of b b-hydroxy-a a-amino acids. Upon treatment with LDA, hydroximates smoothly underwent the rearrangement to give Z-2-hydroxyoxime ethers in good yield, which were converted into both cis-and trans-oxazolidinones with high stereoselectivity. The cis-and trans-oxazolidino...

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Section: Methodsmentioning

confidence: 99%

Section: Preparation Of Hydroximates 1a-cmentioning

confidence: 99%

Section: Preparation Of Hydroximates 1a-cmentioning

confidence: 99%

Section: Preparation Of Hydroximates 1a-cmentioning

confidence: 99%

mentioning

confidence: 99%

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Stereoselective Synthesis of .BETA.-Hydroxyphenylalanines Using Imino 1,2-Wittig Rearrangement of Hydroximates

Miyata

Asai

Naito

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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Methods for the Chemical Synthesis of Noncoded α‐Amino Acids found in Natural Product Peptides

Habay

Park

Kennedy

et al. 2009

Amino Acids, Peptides and Proteins in Organic Chemistry

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Synthesis of Diheteroatomic Five‐Membered Heterocyclic Compounds from α,β‐Unsaturated Aldehydes

Keiko

Вчисло

2016

Asian J Org Chem

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The recent increasei ni nterest in the chemistry of azoles has been owing to their paramount importance in several essential fields of research, such as pharmacology, medicine, biology, the organic synthesis of fine chemicals, agriculturalc hemistry, and the chemical industry.T his Focus Review summarizes and highlights recently developed methods for the synthesis of five-membered N,N-, N,O-, andN ,Sheterocycles based on the transformations of 2-alkenals. Over the last 15 years, these reactions, which often differ from reactions involving other a,b-unsaturatedc arbonyl compoundsi nt erms of methoda nd results, have gathered significant momentum. The multitude of catalytic and tech-nological novelties discussed in this Focus Review,s uch as asymmetricm etal-and organocatalysis,o ne-pot multicomponent reactions that proceed through domino, cascade, or tandem sequences, and microwave activation,p romote the formation of ad iverse range of target products, the structures of which becomec lear from the mechanistic schemes given in this Focus Review.T he mechanisms discussed reflect great advances in the chemo-, regio-, and stereoselectivity of the reactions of 2-alkenals, which allows new azoles and related compounds (imidazoles, pyrazoles, oxazoles, thiazoles, and their hydrogenatedd erivatives) to be synthesized.[a] Prof.The ORCID identification number(s) for the author(s) of this articlecan be found under http://dx.Scheme2.One-potsynthesis of imidazoles 8 and tentativemechanism of the reaction.T s= 4-toluenesulfonyl, TMS = tert-butyltrimethylsilyl, Bn = benzyl, Lg = leaving group.Scheme3.Enantioselective synthesiso f3-hydroxyalkyl and 3-aminoalkyli midazo[1,2-a]pyridines (9)through an asymmetricorganocatalytic [3+ +2] annulation strategy.Alk = alkyl.Scheme4.One-potsynthesis of imidazole-containingc ondensed heterocycles by the reaction of 2-alkoxypropenalswith N-binucleophiles.Scheme9.Aroute to 2-(1'-alkoxyvinyl)imidazolidines 27 through the condensation of alkoxy propenals.

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Application of enantiopure templated azomethine ylids to β-hydroxy-α-amino acid synthesis

Cited by 40 publications

References 22 publications

Stereoselective Synthesis of .BETA.-Hydroxyphenylalanines Using Imino 1,2-Wittig Rearrangement of Hydroximates

Stereoselective Synthesis of .BETA.-Hydroxyphenylalanines Using Imino 1,2-Wittig Rearrangement of Hydroximates

Methods for the Chemical Synthesis of Noncoded α‐Amino Acids found in Natural Product Peptides

Synthesis of Diheteroatomic Five‐Membered Heterocyclic Compounds from α,β‐Unsaturated Aldehydes

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