A Novel Synthesis of α,β-Unsaturated Aldehydes and  Esters by Dye-Photooxygenation of Methyl Enol Ethers

Rousseau, G.; Perchec, P. Le; Conia, J. M.

doi:10.1055/s-1978-24681

Cited by 39 publications

(1 citation statement)

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“…It is well known that allylic peroxides are prone to undergoing many transformations, [18][19][20][21][22][23][24][25][26] such as Hock-Cleavage to form dicarbonyl fragments, catalyzed by acid or even in the absence of any added acid, e.g. in case of 4, this will generate diosone 5, peroxide bond homolysis to form enones or enols catalyzed by trace quantities of metals, Kornblum-DeLaMare Dehydration for allylic peroxides having α-hydrogens to form enones catalyzed by base preferably in the presence of acetyl chloride or acetic anhydride.…”

Section: Scheme 2 Photooxygenation Of 23-dihydrofurans and 34dihydrmentioning

confidence: 99%

An Environmentally Friendly Process for the Preparation of 16‐Dehydropregnenolone Acetate

Zhang

Liu

Xue-Xin³

et al. 2005

Chin. J. Chem.

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Instead of environmentally toxic chromium oxidant, singlet oxygen generated photochemically was used as environmentally friendly and benign oxidizing agent to accomplish the transformation of pseudodiosgenin diacetate to diosone efficiently in a low toxic and less expensive solvent acetone. Accordingly 16-dehydropregnenolone acetate (16-DPA), an important intermediate for preparation of steroidal drugs, was prepared in good yield (75%) when photoreaction was run in acetone/acetic anhydride/pyridine system. The mild reaction condition as well as simple and environmentally friendly process made the method commercially viable and important for production of 16-DPA in industrial scale.

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Section: Scheme 2 Photooxygenation Of 23-dihydrofurans and 34dihydrmentioning

confidence: 99%

An Environmentally Friendly Process for the Preparation of 16‐Dehydropregnenolone Acetate

Zhang

Liu

Xue-Xin³

et al. 2005

Chin. J. Chem.

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Artemisinin Tricyclic Analogs Bearing a Methyl Group at C-5a: Preparation and Antimalarial Activity

Zouhiri

Desmaële

d’Angelo³

et al. 1998

Eur. J. Org. Chem.

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Syntheses of the two artemisinin tricyclic analogs 39 and 40 bearing a methyl group at C‐5a have been accomplished. The common starting material in both approaches was enantiomerically pure oxo nitrile (R)‐10 which was elaborated through the Michael addition of chiral imine 9 to acrylonitrile. Several strategies for converting 10 into targets 39 and 40 were investigated. The strategy which was ultimately adopted employed the addition of [chloro(trimethylsilyl)methyl]lithium (15) to 10. The resulting epoxysilane 16 was converted into vinylsilane 36 by an original route involving first the regioselective opening of the oxirane ring by means of HBr, followed by zinc reduction. Addition of methyllithium to form 36 furnished pivotal derivative 37 which was finally converted into our targets 39 and 40 by ozonization. These trioxanes were thus synthesized by a linear sequence of seven chemical operations, with an overall yield of ca. 9% and 11%, respectively, from 2‐methylcyclohexanone (8). Both compounds proved to be completely devoid of antimalarial activity on the “H” clone of Plasmodium falciparum. In contrast, the two structural analogs 43 and 44 having a hydrogen atom at the C‐5a angular position display relatively high antimalarial activities. Thus, the fact that the replacement of the hydrogen atom at C‐5a by a methyl group in tricyclic trioxanes 6 was detrimental to biological activity reinforced the hypothesis that tight hemin‐trioxane complexes of type 7 are involved in the activation phase of these antimalarial agents.

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The Saegusa Oxidation and Related Procedures

Bras

Мuzart

2019

Organic Reactions

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A Novel Synthesis of α,β-Unsaturated Aldehydes and Esters by Dye-Photooxygenation of Methyl Enol Ethers

Cited by 39 publications

References 0 publications

An Environmentally Friendly Process for the Preparation of 16‐Dehydropregnenolone Acetate

An Environmentally Friendly Process for the Preparation of 16‐Dehydropregnenolone Acetate

Artemisinin Tricyclic Analogs Bearing a Methyl Group at C-5a: Preparation and Antimalarial Activity

The Saegusa Oxidation and Related Procedures

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