Enantioselective Synthesis of Imperanene, a Platelet Aggregation Inhibitor

Shattuck, James C.; Shreve, Cheney; Solomon, Sandra E.

doi:10.1021/ol0164482

Cited by 20 publications

(19 citation statements)

References 19 publications

(13 reference statements)

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“…A similar procedure with BH 3 ‐THF/30% H 2 O 2 , NaOH was used to obtain 5 . The t ‐butyldimethysilyl ether 8 was obtained by using TBDMSCl and imidazole as described by Shattuck et al 28 Compound 10 was synthesized according to the procedure of Varma and Narayanan29 using chloroacetic acid and NaOH.…”

Section: Methodsmentioning

confidence: 99%

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Structure–activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae

Barbosa

Silva

Alves

et al. 2012

Pest Management Science

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Section: Methodsmentioning

confidence: 99%

“…1‐{[(1,1‐Dimethylethyl)dimethylsilyl]oxy}‐2‐methoxy‐4‐(2‐propen‐1‐yl)‐benzene ( 8 ) was prepared from eugenol using the method of Shattuck et al 28 Colorless oil (91%). IR (film, cm −1 )2956, 2932, 2858.…”

Section: Methodsmentioning

confidence: 99%

Structure–activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae

Barbosa

Silva

Alves

et al. 2012

Pest Management Science

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“…Optically pure (R)-3 n, the key synthetic intermediate of (+)-tanikolide, which employed the less expensive cyclohexenone as the starting material, was produced in twice the previously obtained yield (entry 14). [24] The combined use of V-MPS and PS-IM for (AE)-8, which was synthesized from vanillin in 95 % overall yield, produced (S)-9 in 88 % yield, which was converted into (S)-10. [22] Our DKR method converted (AE)-1 p into (R)-3 p in 90 % yield and 97 % ee (entry 16).…”

mentioning

confidence: 99%

A Mesoporous‐Silica‐Immobilized Oxovanadium Cocatalyst for the Lipase‐Catalyzed Dynamic Kinetic Resolution of Racemic Alcohols

Egi¹,

Sugiyama²,

Saneto³

et al. 2013

Angew Chem Int Ed

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In the last decade, cooperative catalysis has received considerable attention as a powerful synthetic method. [1] Two or more catalysts function simultaneously or sequentially in a single reaction vessel to construct complicated molecules, which provides a means to perform unprecedented syntheses that cannot be achieved by a single catalyst. Various catalytic combinations involving transition metals, organocatalysts, and biocatalysts have been developed thus far. [2] A typical example is the combined use of lipases and transition metals to attain the dynamic kinetic resolution (DKR) of racemic secondary alcohols for producing single enantiomer products in up to 100 % yields, [3] in contrast to the use of lipases alone, which can only achieve maximum yields of 50 %. In this DKR process, the enzymatic enantioselective esterification of racemic alcohols is combined with the transition-metal-catalyzed continuous racemization of optically active alcohols, which remain intact during the enzymatic reaction, through a redox process. However, such cooperative cocatalysis often encounters crucial issues of low compatibility between the lipases and the transition metals. Although intense efforts have been devoted to developing highly active racemization catalysts, [4, 5] only a few ruthenium complexes have met both the requirement of sufficient compatibility with lipases and high racemization activity. [5] We recently reported that a combination of oxovanadium compounds (4 or 5) with lipases accomplished the efficient and direct conversion of racemic allylic alcohols (AE)-1 and (AE)-2 into optically active allyl esters (R)-3. [6] This method featured a unique racemization process wherein 4 (or 5) catalyzed the racemization of (S)-1 with 1,3-transposition of the hydroxy group of 1 or 2, while the lipases effected chemoand enantioselective esterification. This is significantly different from the above-mentioned ruthenium-catalyzed DKRs and offered a synthetic advantage in that both (AE)-1 and (AE)-2 were available as equivalent substrates. However, this method required further improvement in both catalytic activity and compatibility of the oxovanadium catalysts with the lipases. [7,8] Herein, we report the preparation of a novel oxovanadium catalyst (V-MPS) immobilized inside mesoporous silica (MPS) with pores of approximately 3 nm in diameter, which enabled a complete division of the racemization site and the enzymatic reaction site. The combined lipase-V-MPS catalyst is reusable and achieved DKR of a wide range of racemic alcohols with excellent chemical and optical yields (Scheme 1).The immobilization of oxovanadium species inside a solid carrier with microsized pores or multilayered structures [9] enables the minimization of interactions between the oxovanadium species and lipases while maintaining easy access of substrate molecules to the metal center. The solid carrier should be neutral and non-charged in order to exert little adverse effect on the lipases. Among the various potential solid carriers, [10,11] MPS,...

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“…Racemic and enantiopure Ipn has been synthesized and characterized by various methods so far [11][12][13][14][15][16]. In these studies, the enantiomeric excess was solely determined by HPLC using either a Chiralcel OD-H, Chiralpak AD-RH, or (R,R)-Whelk-O 1 chiral analytical column coupled to UV detection at 254 nm [12][13][14]16].…”

mentioning

confidence: 99%

Chiral recognition of imperanene enantiomers by various cyclodextrins: A capillary electrophoresis and NMR spectroscopy study

et al. 2012

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The enantiomers of imperanene, a novel polyphenolic compound of Imperata cylindrica (L.), were separated via cyclodextrin-modified capillary electrophoresis. The anionic form of the analyte at pH 9.0 was subject to complexation and enantioseparation CE studies with neutral and charged cyclodextrins. As chiral selectors 27 CDs were applied differing in cavity size, sidechain, degree of substitution (DS) and charge. Three hydroxypropylated and three sulfoalkylated CD preparations provided enantioseparation and the migration order was successfully interpreted in each case in terms of complex mobilities and stability constants. The best enantioresolution (R(S) = 1.26) was achieved using sulfobutyl-ether-γ-CD (DS ∼4), but it could be enhanced by extensive investigations on dual selector systems. After optimization (CD concentrations and pH) R(S) = 4.47 was achieved using a 12.5 mM sulfobutyl-ether-γ-CD and 10 mM 6-monodeoxy-6-mono-(3-hydroxy)-propylamino-β-cyclodextrin dual system. The average stoichiometry of the complex was determined with Job's method using NMR-titration and resulted in a 1:1 complex for both (2-hydroxy)propyl-β- and sulfobutyl-ether-γ-CD. Further NMR experiments suggest that the coniferyl moiety of imperanene is involved in the host-guest interaction.

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Enantioselective Synthesis of Imperanene, a Platelet Aggregation Inhibitor

Cited by 20 publications

References 19 publications

Structure–activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae

Structure–activity relationships of eugenol derivatives against Aedes aegypti (Diptera: Culicidae) larvae

A Mesoporous‐Silica‐Immobilized Oxovanadium Cocatalyst for the Lipase‐Catalyzed Dynamic Kinetic Resolution of Racemic Alcohols

Chiral recognition of imperanene enantiomers by various cyclodextrins: A capillary electrophoresis and NMR spectroscopy study

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