Synthesis of chiral adenosine receptor recognition units via a sharpless asymmetric epoxidation procedure

Lentz, Nelsen L.; Peet, Norton P.

doi:10.1016/s0040-4039(00)94634-3

Cited by 18 publications

(4 citation statements)

References 9 publications

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“…Treatment of (carbethoxymethylene) triphenylphosphorane with phenylacetaldehyde in dry benzene at room temperature gave a mixture of trans - and cis -olefins which were separated by flash chromatography (hexanes−ether, 10:1 v/v): ethyl trans -4-phenyl-2-butenoate (89% yield) as a colorless oil, R f = 0.31 (hexanes−ether, 10:1 v/v). DIBAL-H reduction of ethyl trans -4-phenyl-2-butenoate in dry ether afforded trans -4-phenyl-2-buten-1-ol (96% yield) as a lightly yellow oil 11b…”

Section: Methodsmentioning

confidence: 99%

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A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes

1998

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A detailed study shows that the chiral ketone catalyzed asymmetric epoxidations of hydroxyalkenes are highly pH dependent. The lower enantioselectivity obtained at low pH is attributed to the substantial contribution of the direct epoxidation by Oxone. At high pH the epoxidation mediated by chiral ketone out-competes the racemic epoxidation, leading to higher enantioselectivity. The effective substrates include allylic alcohol, homoallylic alcohol, and bishomoallylic alcohol. In most cases, over 90% ee was obtained.

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Section: Methodsmentioning

confidence: 99%

“…( R , R )-3-(Phenylmethyl)oxiranemethanol (Table , entry 2): colorless oil; [α] D 23 = +34.1° ( c 1.27, CHCl 3 ) [lit 11a…”

Section: Methodsmentioning

confidence: 99%

A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes

1998

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“…Chart 5 summarizes the synthesis of alkyne 57, 44) starting with the known allyl alcohol 52. 45) Catalytic asymmetric epoxidation of 52 under Sharpless conditions 46) provided epoxy alcohol 53 in 91% yield and 92% ee. Enantiomeric excess could be enhanced to 100% upon recrystallization of the derived 3,5-dinitrobenzoate 54.…”

Section: The Aldol Approach To Zaragozic Acid Cmentioning

confidence: 99%

Total Synthesis of the Squalene Synthase Inhibitor Zaragozic Acid C

Nakamura

2005

CHEMICAL & PHARMACEUTICAL BULLETIN

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Zaragozic acids and squalestatins were documented by Merck, Glaxo, and Tokyo Noko University/Mitsubishi Kasei Corporation as part of a program aimed at identifying novel inhibitors of squalene synthase, as well as farnesyl transferase. These natural products have attracted considerable attention from numerous synthetic chemists because of their therapeutic potential and novel architecture. This review highlights our total syntheses of zaragozic acid C by two convergent strategies. The key steps in our first-generation synthesis involve 1) simultaneous creation of the C4 and C5 quaternary stereocenters through the Sn(OTf) 2 -promoted aldol coupling reaction between the a a-keto ester and silyl ketene thioacetal derived from L-and D-tartaric acids, respectively; and 2) construction of the bicyclic core structure via acid-catalyzed internal ketalization under kinetically controlled conditions. The second-generation strategy relies on a tandem carbonyl ylide formation/1,3-dipolar cycloaddition approach and features elongation of the C1 alkyl side chain through an olefin cross-metathesis as well as high convergency and flexibility.

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“…l 1 However, we have found no detailed description on the asymmetric epoxidation of trans-4-phenyl-2-buten-1-01, and the isolation and characterization of chral3-benzylglycidol despite several disclosures on the use of this reaction for HIV protease inhibitor syntheses's2 and other epoxide application studies. 12,13 This paper describes the detailed synthesis of chiral 3-benzylglycidol using a work-up procedure that is amenable for process scale-up, and the appropriate analytical methods for the determination of its enantiomeric purity and diastereomeric purity.…”

mentioning

confidence: 99%

Synthesis and enantiomeric purity determination of chiral 3‐benzylglycidol, a key synthon for hiv protease inhibitors

Shum¹,

Chen²,

Cannarsa³

1994

Chirality

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The detailed synthesis of (2R,3R)-3-benzylglycidol by the Sharpless asymmetric epoxidation route is described. The enantiomeric purity determination of this compound is complicated by the presence of small quantities of the diastereometric (2R,3S)-3-benzylglycidol from the asymmetric epoxidation of the cis-allylic alcohol, and the unreacted allylic alcohols that are not removed in the product isolation steps. We have developed a direct chiral HPLC method that can resolve all these components for the precise determination of enantiomeric excesses of chiral 3-benzylglycidols.

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Synthesis of chiral adenosine receptor recognition units via a sharpless asymmetric epoxidation procedure

Cited by 18 publications

References 9 publications

A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes

A pH Study on the Chiral Ketone Catalyzed Asymmetric Epoxidation of Hydroxyalkenes

Total Synthesis of the Squalene Synthase Inhibitor Zaragozic Acid C

Synthesis and enantiomeric purity determination of chiral 3‐benzylglycidol, a key synthon for hiv protease inhibitors

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