Ruthenium-catalyzed reduction of N-alkoxy- and N-hydroxyamides

Fukuzawa, Hiroko; Ura, Yasuyuki; Kataoka, Yasutaka

doi:10.1016/j.jorganchem.2011.08.026

“…The oxindole 11 f was then reacted with the boronic acid 16 under Suzuki coupling conditions to afford the precursor 17 in 72 % yield. [26] It was found that when the substituent on the anilide nitrogen atom was either H, methyl, benzyl, or methoxy,t he reaction did not afford the desired product 8.Inaddition, an attempt with N-benzyl-2-bromo-N-hydroxy-2-methylpropanamide (18)u nder the standard reaction conditions to prepare the six-membered ring compound 19 gave the olefin 20 in almost quantitative yield without even trace amount of 19 formed (Scheme 5). [26] It was found that when the substituent on the anilide nitrogen atom was either H, methyl, benzyl, or methoxy,t he reaction did not afford the desired product 8.Inaddition, an attempt with N-benzyl-2-bromo-N-hydroxy-2-methylpropanamide (18)u nder the standard reaction conditions to prepare the six-membered ring compound 19 gave the olefin 20 in almost quantitative yield without even trace amount of 19 formed (Scheme 5).…”

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confidence: 99%

Transition‐Metal‐Free Synthesis of N‐Hydroxy Oxindoles by an Aza‐Nazarov‐Type Reaction Involving Azaoxyallyl Cations

Ji

¹

,

Liu

²

,

Liao

³

2016

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An ovel transition-metal-free method to construct N-hydroxy oxindoles by an aza-Nazarov-type reaction involving azaoxyallyl cation intermediates is described. Avariety of functional groups were tolerated under the weak basic reaction conditions and at room temperature.Aone-pot process was also developed to make the reaction even more practical. This method provides alternative access to oxindoles and their biologically active derivatives.

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“…The oxindole 11 f was then reacted with the boronic acid 16 under Suzuki coupling conditions to afford the precursor 17 in 72 % yield . Cleavage of the N−O bond of 17 afforded 5 in 81 % yield …”

Section: Figurementioning

confidence: 99%

Transition‐Metal‐Free Synthesis of N‐Hydroxy Oxindoles by an Aza‐Nazarov‐Type Reaction Involving Azaoxyallyl Cations

Ji

¹

,

Liu

²

,

Liao

³

2016

View full text Add to dashboard Cite

An ovel transition-metal-free method to construct N-hydroxy oxindoles by an aza-Nazarov-type reaction involving azaoxyallyl cation intermediates is described. Avariety of functional groups were tolerated under the weak basic reaction conditions and at room temperature.Aone-pot process was also developed to make the reaction even more practical. This method provides alternative access to oxindoles and their biologically active derivatives.

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“…Cinnamamide 1p afforded the corresponding product without the reduction of the olefin moiety. 10 It is worth noting that the demethoxylation of enolisable N-methyl-N-methoxyamides 1qs proceeded smoothly, and no side reactions were observed.…”

mentioning

confidence: 93%

“…Dealkoxylation proceeded in alcoholic solvents, which also behaved as a stoichiometric reductant. 10 Although the catalytic reactions require only green and cheap alcohols as stoichiometric reductants, it is necessary to add a substoichiometric amount of Zn-Cu for activating the ruthenium catalyst. Herein, we report the palladium-catalysed dealkoxylation of N-alkoxyamides in the absence of an external reductant as a convenient and reductant-free protocol for dealkoxylation (Scheme 2c).…”

mentioning

confidence: 99%