- A Method for the Preparation of β-Amino-α,β-unsaturated Carbonyl Compounds: Study of Solvent Effect and Mechanism
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An efficient method for the preparation of β-amino-α,β-unsaturated carbonyl compounds is demonstrated. Bench-stable sodium 3-oxo-enolates were prepared from carbonyl compounds, and reacted with amines in the presence of an acid and a desiccant. DFT studie
- R. S., Reyno,Sugunan, Akash,S., Ranganayakulu,Suresh, Cherumuttathu H.,Rajendar, Goreti
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supporting information
p. 1040 - 1045
(2020/02/15)
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- Scalable synthesis of highly reactive 1,3-diamino dienes from vinamidinium salts and their use in Diels-Alder reactions
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A practical and chromatography-free synthesis of vinamidinium salts and their use as diene precursors in Diels-Alder reactions is reported. Additionally, 1,3-dipyrrolidino-1,3-butadiene was shown to be significantly more reactive than Rawal's diene in a c
- Zhou, Sida,Sanchez-Larios, Eduardo,Gravel, Michel
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experimental part
p. 3576 - 3582
(2012/06/15)
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- Synthesis of stacked 'push-pull' acetylenes
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In view of possible solid-state polymerizations of crystalline stacked 'push-pull'-acetylenes 1, a series of compounds 1 has been synthesized (Scheme 3), and the results of X-ray analyses of 'push-pull'-acetylenes 1d,e,f are discussed. Of these three compounds, methyl 2-morpholinoacetylene carboxylate (1d) is by far the best candidate giving crystals with nicely stacked molecules (Fig. 3), Even in this case, however, stacking parameters d = 4,12 A and a = 31,6°are too large for allowing solid-state polymerizations.
- Berger, Daniel,Wilhelm, Patrick,Neuenschwander, Markus
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p. 326 - 337
(2007/10/03)
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- Additions of nucleophiles to 3-oxo-2,3-dihydrothiophene 1,1-dioxides. Formation of vinyl sulfides, thioacetals and enaminones
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3-Oxo-2,3-dihydrothiophene 1,1-dioxide (la) was prepared by oxidation of the commercially available 3methoxythiophene with dimethyldioxirane. Some other substituted 3-methoxythiophene derivatives were oxidized as well. Although the yields of these reactio
- Hofslokkcn, Nini Unn,Skattebol, Lars
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p. 3085 - 3088
(2007/10/03)
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- 1-amino-3-siloxy-1,3-butadienes: Highly reactive dienes for the Diels- Alder reaction
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1-Amino-3-siloxy-1,3-butadienes represent a novel class of heteroatom- containing dienes with several useful properties. These dienes can be prepared efficiently by deprotonation of readily available vinylogous amides with potassium hexamethylsilazide, followed by silylation of the corresponding potassium enolates. This protocol has been found to be quite general for the preparation of various dienes containing different silyl and amino groups. Amino siloxy dienes readily undergo [4 + 2] cycloadditions with a wide range of electron-deficient dienophiles. The reactions generally occur under very mild conditions to afford the corresponding [4 + 2] adducts in high yields and with complete regioselectivity. High endo selectivity is observed in the case of N-phenylmaleimide and methacrolein. Other cycloadducts are usually obtained as mixtures of endo/exo diastereomers. The cycloadducts are versatile synthetic intermediates. They can be subjected to deprotonation, reduction, and Wittig olefination without any hydrolysis or elimination. In addition, the elimination of the amino group can be cleanly accomplished under acidic conditions leading to the formation of enones. A variety of substituted cyclohexenones can be prepared by this procedure.
- Kozmin, Sergey A.,Janey, Jacob M.,Rawal, Viresh H.
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p. 3039 - 3052
(2007/10/03)
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- Michael additions to 3(2H)-thiophenone 1,1-dioxide
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The addition of thiols and amines to 3(2H)thiophenone 1,1-dioxide takes place with extrusion of sulfur dioxide, furnishing in high yields the corresponding vinyl sulfides and enamines. Addition of dithiols afforded the corresponding thioacetals. The rates of the Michael addition and the extrusion reaction are strongly influenced by the solvent employed. In ethanol, sulfur dioxide extrusion took place even at room temperature.
- Hofslokken, Nini,Flock, Solveig,Skattebo, Lars
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p. 119 - 122
(2007/10/02)
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