- Process for preparing dihydropyrane compound
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To provide a simple process for economically preparing a dihydropyrane compound at a high productivity and a high reaction yield. To use a compound selected from the group consisting of a base and a compound (VIII) having a weaker coordination power to the Lewis acid than the aldehyde compound and having an activity to dissolve the Lewis acid, coordinated by the compound (VIII), in a solvent as a co-catalyst in reacting aldehyde with a diene compound in the presence of a Lewis acid to prepare a 5,6-dihydro-2H-pyrane compound represented by formula (III): STR1 in which R1 represents a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, aryl group which may be substituted with alkyl group, having 6 to 12 total carbon atoms; R2 and R3 represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.
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- 4-(Arylsulfonyl)glycals in synthesis. Cation-mediated synthesis of 2,6- disubstituted dihydropyrans
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4-(Arylsulfonyl)glycal 9, easily prepared from phenylsulfinic acid, acrolein and 2-phenyloxirane, undergoes efficient, stereoselective S(N)1' reactions on exposure to Lewis acidic reagent systems. Treatment of syn-9 with dimethyldioxirane gives a single glycal epoxide, which also is a substrate for intermolecular C-glycosidation reactions.
- Bailey, Jennifer M.,Craig, Donald,Gallagher, Peter T.
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p. 132 - 134
(2007/10/03)
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- Trifluoromethanesulfonic acid, an efficient catalyst for the hetero Diels-Alder reaction and an improved synthesis of mefrosol
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Trifluoromethanesulfonic (triflic) acid (1 mol%) has been found to be an efficient catalyst for the hetero Diels-Alder reaction between aromatic aldehydes and unactivated dienes.
- Aggarwal, Varinder K.,Vennall, Graham P.,Davey, Paul N.,Newman, Chris
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p. 2569 - 2572
(2007/10/03)
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- Cationic palladium(II) complex-catalyzed hetero Diels-Alder reaction of dienes with aldehydes
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Cationic palladium(II) complexes, [PdL2(RCN)2](BF4)2, have been found to catalyze the hetero Diels-Alder reaction of nonactivated simple dienes with aldehydes, affording the corresponding 5,6-dihydro-2H-pyrans in good yields under mild conditions.
- Oi, Shuichi,Kashiwagi, Kenji,Terada, Eiji,Ohuchi, Kazuei,Inoue, Yoshio
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p. 6351 - 6354
(2007/10/03)
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- CONCERNING THE PRODUCTS OBTAINED FROM THE CONDENSATION OF 4-METHYL-4-PENTEN-2-OL WITH BENZALDEHYDE
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The products formed in the condensation reaction of 4-methyl-4-penten-2-ol with benzaldehyde were reinvestigated.Their constitutions and configurations were determined spectroscopically.For further characterisation, the three olefins 8-10 were epoxidised.
- Schneider, Andreas,Sequin, Urs
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p. 949 - 953
(2007/10/02)
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