Regiospecific α-hexafluoroisopropylidenation of ketones using hexafluoroacetone

Ishihara, Takashi; Shinjo, Hiroshi; Inoue, Yoshihisa; Ando, Teiichi

doi:10.1016/s0022-1139(00)81485-2

Cited by 30 publications

(2 citation statements)

References 11 publications

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“…These unsaturated ketones were reduced with tin(II) chloride and cyclized to the desired thiophenes with phosphorus pentasulfide. 39 The reaction of (Z)-a-fluoro- 3 Synthesis of Perfluoroalkylthiophenes…”

Section: Heterocyclizationmentioning

confidence: 99%

Synthesis of Fluorinated Thiophenes and Their Analogues

Serdyuk¹,

Абаев²,

Бутин³

et al. 2011

Synthesis

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Section: Heterocyclizationmentioning

confidence: 99%

Synthesis of Fluorinated Thiophenes and Their Analogues

Serdyuk¹,

Абаев²,

Бутин³

et al. 2011

Synthesis

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“…Still and his group also used the stabilising effect of a hetero-atom in their successful synthesis of TxA, via (8).' (7)…”

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confidence: 99%

Stabilisation of the thromboxane ring system by electron-withdrawing substituents: synthesis and attempted cyclisation of substituted tetrahydropyran-2,4-diols

Kirby¹,

Ryder²,

Matassa³

1990

J. Chem. Soc., Perkin Trans. 1

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The hetero Diels-Alder reaction of trifluoromethyl ketones and 1benzyloxy-3-trimethylsilyloxybutadiene is developed as a route to 4hydroxytetrahydropyranyl acetal derivatives. Several 6,6-disubstituted tetrahydropyran-2,4-diols have been prepared, and their anomeric equilibria measured by 'H NMR spectroscopy. Attempted cyclodehydration to 2,6-dioxabicyclo[3.1.1] heptanes (thromboxane A, analogues) failed under various conditions.The study of the potent platelet aggregating factor and vasoconstrictor thromboxane A2 (TxA,; 1) is complicated by its short lifetim-f the order of 30s under physiological conditions.' This is an intrinsic property of the oxetane acetal system,2 and a severe restriction on the design of potential antagonists. As a result, several groups have made analogues with one or both of the acetal oxygen atoms replaced by carbon3 or sulphur.'We are interested in stabilising the oxetane acetal ring system by appropriate substitution. Electron-withdrawing substituents like the OH groups of sugars have a large stabilising effect on tetrahydropyranyl acetals.' This is a result of inductive destabilisation of the developing oxocarbocation always involved in acetal cleavage. In a preliminary study we showed that the trifluoroethyl oxetane acetal(2; R = CH,CF3) is hydrolysed some 5000 times more slowly than the corresponding methoxy derivative (& R = CH3).6This paper describes the synthesis of a serics of tetrahydropyranyl acetals (3) and hemiacetals (3; X = H), with one or two CF3 groups in the corresponding 6 position, designed as precursors to stabilised oxetane acetals (4).Our route to compounds (3) is based on the hetero Diels-Alder reactions of trifluoromethyl ketones with suitable alkoxy and silyloxy dienes. Ishihara and co-workers' have reported that hexafluoroacetone reacts with dienol silyl ethers such as (5),

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2-Trimethylsilyloxy-1,3-butadiene

Jung

2001

Encyclopedia of Reagents for Organic Synthesis

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Regiospecific α-hexafluoroisopropylidenation of ketones using hexafluoroacetone

Cited by 30 publications

References 11 publications

Synthesis of Fluorinated Thiophenes and Their Analogues

Synthesis of Fluorinated Thiophenes and Their Analogues

Stabilisation of the thromboxane ring system by electron-withdrawing substituents: synthesis and attempted cyclisation of substituted tetrahydropyran-2,4-diols

2-Trimethylsilyloxy-1,3-butadiene

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