Synthesis of Enantiopure 9‐Oxabicyclononanediol Derivatives by Lipase‐Catalyzed Transformations and Determination of Their Absolute Configuration

Hegemann, Klaus; Fröhlich, Roland; Haufe, Günter

doi:10.1002/ejoc.200300783

Cited by 19 publications

(20 citation statements)

References 52 publications

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“…Compound XI resembles its bromosubstituted analog [26]. By contrast, isomeric 2,6-diiodo-9-oxabicyclo[3.3.1]nonane exists in a boat conformation [27]. The geometric parameters of molecules X and XI are listed in table.…”

Section: Methodsmentioning

confidence: 99%

Reaction of trifluoromethanesulfonamide with alkenes and cycloocta-1,5-diene under oxidative conditions. Direct assembly of 9-heterobicyclo[4.2.1]nonanes

2011

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Reactions of trifluoromethanesulfonamide with α-methylstyrene, 2-methylpent-1-ene, and cycloocta-1,5-diene in the system t-BuOCl-NaI were studied. In the reaction with α-methylstyrene 1-iodo-2-phenylpropan-2-ol was the only isolated product. The reaction with 2-methylpent-1-ene gave a mixture of N,N′-(2-methylpentane-1,2-diyl)bis(trifluoromethanesulfonamide), trifluoro-N-(2-hydroxy-2-methylpentyl)-methanesulfonamide, and N, N′-[oxybis(2-methylpentan-2,1-diyl)]bis(trifluoromethanesulfonamide). Trifluoromethanesulfonamide reacted with cycloocta-1,5-diene to produce a mixture of 2,5-diiodo-9-(trifluoromethylsulfonyl)-9-azabicyclo[4.2.1]nonane and 2,5-diiodo-9-oxabicyclo[4.2.1]nonane; this reaction may be regarded as the first example of direct assembly of bicyclononane skeleton.We recently showed that aziridination of styrene with trifluoromethanesulfonamide in the oxidative system t-BuOCl-NaI · 2 H 2 O leads to formation of both linear structures I and II and heterocyclization product, 2,5-diphenyl-1,4-bis(trifluoromethylsulfonyl)piperazine (III) [1]. The structure of III was proved by X-ray analysis, and a mechanism involving intermediate formation of 2-phenyl-1-trifluoromethylaziridine was proposed [1]. However, the formation of substituted piperazine instead of expected aziridine contradicted the data reported by Minakata et al. [2], according to which aziridines were obtained in reactions of styrene and other alkenes with sulfonamides under analogous conditions due to strong electron-withdrawing effect of the CF 3 group [1]. We tried to reproduce the conditions described in [2] more accurately and carried out the reaction of styrene with trifluoromethanesulfonamide in the presence of anhydrous sodium iodide. In this case, we isolated compounds I and II and 2,6-diphenyl-1,4-bis(trifluoromethylsulfonyl)piperazine (IV) which is isomeric to III [3].In the present work we studied reactions of trifluoromethanesulfonamide with α-methylstyrene, 2-methylpent-1-ene, and cycloocta-1,5-diene under oxidative conditions (in the presence of t-BuOCl-NaI or t-BuOCl-NaI · 2 H 2 O) and analyzed possible ways of formation of the corresponding products.Taking into account that α-methylstyrene reacted with trifluoromethanesulfonamide in a way similar to styrene [2], i.e., with formation of the corresponding aziridine, and that the reaction direction strongly depends on the composition of the oxidative system, α-methylstyrene (V) was brought into reaction with trifluoromethanesulfonamide in two systems containing NaI · 2H 2 O or anhydrous NaI (as in [2]). In both cases, the only product was 1-iodo-2-phenylpropan-2-ol (VI) (Scheme 1). Compound VI is likely to be formed via iodination of α-methylstyrene with t-BuOI to

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Section: Methodsmentioning

confidence: 99%

Reaction of trifluoromethanesulfonamide with alkenes and cycloocta-1,5-diene under oxidative conditions. Direct assembly of 9-heterobicyclo[4.2.1]nonanes

2011

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“…The probes used were ATB and SW, with 5 mm internal diameter, at room temperature with 45° pulse for hydrogen and carbon. Chemical displacements (d) in 1 The isomeric mixture of 9-oxabicyclo[3.3.1]nonane-2,6-diol (3) and 9-oxabicyclo[4.2.1]nonane-2,5-diol (3a) was prepared by the oxidation of cycloocta-5-diene (2) (1.18 mol) under treatment with formic acid [9][10][11] (1.06 mol) and under vigorous magnetic stirring and, in an ice bath, 30% H 2 O 2 (300 mL, 9.20 mol) was added dropwise. After the addition, the formation of a biphasic mixture was observed, which was maintained at 50 °C (internal temperature).…”

Section: General Methodsmentioning

confidence: 99%

Synthesis and Expansion of Bicyclic Enol Ether: A Probable Precursor for the Synthesis of Macrolide (±)-Pyrenophorin

Costa¹,

Martins²,

ARAUJO³

et al. 2017

J. Braz. Chem. Soc.

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A convenient procedure for the synthesis and expansion of bicyclic rings has been developed for the production of probable precursors of non-racemic pyrenophorin, an antibiotic dilactone. The major highlight for this new synthetic methodology came from the use of a readily available reagent of easy manipulation, 9-oxabicyclo[3.3.1]nonane-2,6-diol, for the preparation of the bicyclic intermediate, which sequentially was subjected to oxidative cleavage with butyl nitrite resulted in an isomeric mixture, a dioximedilactone and diisoxazoledilactone.

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“…(75). Selective acylation at the (R)-centers using CRL gave the corresponding enantioenriched compounds 46-49 [189][190]. Oxidation of monoalcohols to 9-oxabicyclononan-2-ones followed by a BaeyerVilliger reaction, led to various γ-butyrolactones, versatile starting materials for natural-product synthesis [191].…”

Section: Prochiral Substratementioning

confidence: 99%

Stereoselective Enzymatic Acylations (Transesterifications)

Chênevert¹,

Pelchat²,

Jacques

2006

COC

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Synthesis of Enantiopure 9‐Oxabicyclononanediol Derivatives by Lipase‐Catalyzed Transformations and Determination of Their Absolute Configuration

Cited by 19 publications

References 52 publications

Reaction of trifluoromethanesulfonamide with alkenes and cycloocta-1,5-diene under oxidative conditions. Direct assembly of 9-heterobicyclo[4.2.1]nonanes

Reaction of trifluoromethanesulfonamide with alkenes and cycloocta-1,5-diene under oxidative conditions. Direct assembly of 9-heterobicyclo[4.2.1]nonanes

Synthesis and Expansion of Bicyclic Enol Ether: A Probable Precursor for the Synthesis of Macrolide (±)-Pyrenophorin

Stereoselective Enzymatic Acylations (Transesterifications)

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