Synthesis of Racemic 3,5-O-Benzylidene-2-deoxypentoses from 2-Phenyl-1,3-dioxan-5-one Hydrate.

Ulven, Trond; Sørbye, Karsten A.; Carlsen, Per H. J.; Rissanen, Kari; Hanfland, Michael; Dooryhée, E.

doi:10.3891/acta.chem.scand.51-1041

Cited by 8 publications

(7 citation statements)

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“…In the first total synthesis of stigmatellin A, a strong inhibitor of the electron transport in chloroplasts and mitochondria, intermediate 41 was cleaved with MMPP to 42 in the presence of the paramethoxbenzyl ether moiety as an alcohol protecting group (Scheme 14). 22 MCPBA and MeCO 3 H. The 3-chloroperoxybenzoic acid (MCPBA) oxidation of DMHs of aromatic aldehydes gives the corresponding nitriles (43)(44)(45)(46)(47)(48)(49)(50)(51) in good yields (Table 2). 23 The oxidation of aliphatic DMHs, however, gave rise to the formation of mixtures of nitriles and aldehydes (see scale to ketone 53 without any epimerization of the axial methyl group (Scheme 15).…”

Section: Oxidative Cleavage Proceduresmentioning

confidence: 99%

Recovery of Carbonyl Compounds from N,N-Dialkylhydrazones

2000

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Deprotonation of enantiomerically pure hydrazones and subsequent trapping with suitable electrophiles generates new stereogenic centers with excellent stereoselectivity. To liberate the original carbonyl functionality in the final products, it is necessary to cleave the hydrazone moiety. In recent years, many reagents have been developed to regenerate carbonyl compounds from the corresponding dialkylhydrazones which are compatible with a wide range of functionalities. This has allowed the use of hydrazones in the total synthesis of complex natural products. This Account is meant to be an overview of methods which are classified as oxidative, hydrolytic, and reductive cleavage procedures.

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Section: Oxidative Cleavage Proceduresmentioning

confidence: 99%

Recovery of Carbonyl Compounds from N,N-Dialkylhydrazones

2000

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“…The SAMP-hydrazone cleavage was achieved using ammonium dihydrogen phosphate buffer according to a method developed by Carlsen et al for dimethylhydrazone cleavage. 16 This method afforded the ketone (R)-6 in 23% yield and 92% ee. Finally, comparison of the rotation values with those given in the literature 7 confirms the absolute configurations given and is in accordance with the established mechanism for the SAMP/RAMP-hydrazone alkylations.…”

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confidence: 99%

First Asymmetric Synthesis of Stigmolone: The Fruiting Body Inducing Pheromone of the Myxobacterium Stigmatella Aurantiaca

Enders¹,

Ridder²

2000

Synthesis

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The asymmetric synthesis of (S)-and (R)-stigmolone [(S)-and (R)-1], an aggregation pheromone of the myxobacterium Stigmatella aurantiaca, starting from 4-methylpentan-2-one is described. The stereogenic centre at the C-5 position of the pheromone was generated via the SAMP/RAMP hydrazone method with high enantiomeric purity. It could be shown again that both enantiomers induce the fruiting body formation of the myxobacterium at concentrations of 1.0-30.0 nM.Myxobacteria like Stigmatella aurantiaca are Gram-negative, sticklike soil bacteria, which live in swarms on insoluble polymer surfaces like rotten wood. Gliding in a swarm has an immense profit for the food intake. This is due to an increase in the local density of secreted hydrolytic enzymes and therefore the amount of available soluble nutrients. The swarm and also the secreted slime serves as a carpet which prevents the loss of enzymes and nutrients. Typically for myxobacteria, S. aurantiaca exists in two different life cycles. In the vegetative growth cycle the population rises like normal bacteria through cell division, but under conditions of starvation the bacteria form multicellular fruiting bodies. 1, 2 These fruiting bodies have a treelike structure and contain the myxospores, which are dormant cells. The change from the vegetative growth to the so-called development cycle is induced by the aggregation pheromone 8-hydroxy-2,5,8-trimethylnonan-4-one, which is named stigmolone after its biological origin and structure according to Plaga et al. Furthermore, this group published the first isolation 3, 4 as well as a synthesis 5 of the racemate of this pheromone.The natural product was isolated in racemic form perhaps due to the extensive isolation and purification procedures and the sensitivity of a-substituted ketones to racemisation. Plaga et al. also discovered an active concentration of 1.0 nM for the fruiting body formation, which makes this pheromone one of the most effective, non-peptidic bacterial pheromones known. 4 Mori et al. reported an 'exchiral-pool' synthesis starting either with (R)-or (S)-citronellol shortly after the first publication of stigmolone. 6, 7 The bioassay of the enantiomers showed the same active concentration for the fruiting body formation as for the racemate and therefore the natural product seemed to be an enantiomeric mixture. 8 For further biological tests Mori et al. developed a new and short synthesis of the racemic pheromone. 9 We now want to present the first asymmetric synthesis of (S)-and (R)-stigmolone [(S)-and (R)-1] and describe the results for the bioassays, which were carried out by Plaga.The target molecule contains one stereogenic centre resulting from the methyl branching at the C-5 position a to the carbonyl group. Therefore, the RAMP/SAMP hydrazone method 10 was chosen to generate both enantiomers of the pheromone based on either enantiomer of the chiral auxiliary. As shown in the Scheme, 4-methylpentan-2-one (2) was treated with (R)-1-amino-2-(methoxymethyl)pyrrolidine (RAMP), both commercially availa...

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“…The intermediates were used as references for determination of the enantiomeric purities in the asymmetric syntheses. Alkylation of 28 with allyl bromide gave the axially substituted 29 , from which racemic 2‐deoxyribose ( 34 ) and 2‐deoxyxylose ( rac ‐ 27 ) were obtained 2. Alkylation of 29 with methyl iodide gave a 4:1 mixture of 30 and 31 .…”

Section: Resultsmentioning

confidence: 99%

“…We have been interested in exploring the synthetic utility of the benzylidene‐protected dihydroxyacetone (BDHA) and its hydrate, 1 . Recently we reported the synthesis of racemic 2‐deoxyribose and 2‐deoxyxylose from the readily available 2‐phenyl‐1,3‐dioxan‐5‐one hydrate ( 1 ) 2. By taking advantage of Enders’ auxiliaries SAMP or RAMP [( S )‐ or ( R )‐1‐amino‐2‐(methoxymethyl)pyrrolidine],3 the enantioselective synthesis of 2‐deoxy‐ L ‐ribose was demonstrated 4.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of All Diastereomers of the 2-Deoxypentoses and the 2,6-Dideoxyhexoses from 2-Phenyl-1,3-dioxan-5-one Hydrate

Ulven

Carlsen

2001

Eur. J. Org. Chem.

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All diastereomers of the 2‐deoxypentoses and the 2,6‐dideoxyhexoses were synthesized from 2‐phenyl‐1,3‐dioxan‐5‐one hydrate (1), by alkylation via the RAMP‐hydrazone (2). Some of the diastereomers were synthesized in the racemic form via the dimethylhydrazone (28). The 2‐deoxypentoses were synthesized by alkylation with allyl bromide, followed by stereoselective reduction, ozonolysis, and deprotection. The 2,6‐dideoxypentoses were synthesized by dialkylation with allyl bromide and methyl iodide.

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Synthesis of Racemic 3,5-O-Benzylidene-2-deoxypentoses from 2-Phenyl-1,3-dioxan-5-one Hydrate.

Cited by 8 publications

References 0 publications

Recovery of Carbonyl Compounds from N,N-Dialkylhydrazones

Recovery of Carbonyl Compounds from N,N-Dialkylhydrazones

First Asymmetric Synthesis of Stigmolone: The Fruiting Body Inducing Pheromone of the Myxobacterium Stigmatella Aurantiaca

Synthesis of All Diastereomers of the 2-Deoxypentoses and the 2,6-Dideoxyhexoses from 2-Phenyl-1,3-dioxan-5-one Hydrate

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