New developments in nucleophilic additions to nitrones

Merino, Pedro

doi:10.1016/j.crci.2005.02.013

Cited by 67 publications

(15 citation statements)

References 41 publications

(30 reference statements)

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“… 8,26 This species could then be engaged by nucleophiles (such as MeMgBr 27 and Et 2 AlCN 28 ) or in a [3 + 2]-cycloaddition reaction 29 with methyl acrylate to afford 63–65 , respectively. 30 All of these latter products were confirmed by X-ray crystallography as possessing the relative configurations shown.…”

Section: Resultsmentioning

confidence: 76%

Synthesis of aza-quaternary centers via Pictet–Spengler reactions of ketonitrones

2021

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Section: Resultsmentioning

confidence: 76%

Synthesis of aza-quaternary centers via Pictet–Spengler reactions of ketonitrones

2021

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“…From a strategic point of view, it was decided to introduce first an N-oxide group and then another substituent taking advantage of the well-known reaction of N-oxide compounds with Grignard reagents. [11] In a first try, we considered the readily commercially available 2,4,6-triphenyl-1,3,5-triazine system (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

1,2‐Dihydrotriazinyl‐N‐oxy Free Radicals

Brough

Gambarelli

Jacquot

et al. 2011

Chemistry A European J

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Triazinyl-N-oxy free radicals, 2-methyl-2,4,6-triphenyl-1,2-dihydro-1,3,5-triazinyl-1-oxy (6a), 2,2,4,6-tetraphenyl-1,2-dihydro-1,3,5-triazinyl-1-oxy (6b), 2,2-dimethyl-4,6-diphenyl-1,2-dihydro-1,3,5-triazinyl-1-oxy (13), and 2,6-dimethyl-2,4-diphenyl-1,2-dihydro-1,3,5-triazinyl-1-oxy (14), in which the unpaired electron is delocalized over three nitrogen atoms, have been prepared and characterized. A method has been devised for introducing an N-oxide function into the triazinyl core. Then, by using a Grignard reagent, substitution α to the N-oxide group was achieved and the resulting 1,2-dihydrotriazine-N-oxide oxidized into the corresponding nitroxide. Solution EPR spectra exhibit hyperfine splitting that confirms spin delocalization over the three nitrogen atoms of the triazinyl ring. They also show that spin delocalization diminishes with increasing distance for the coupling and is largest for nitrogen N1 and weakest for N5. Free radicals 6a and 13 are stable in the solid state and have been characterized by X-ray diffraction, but they tend to gradually degrade in solution. In the solid state, these two free radicals are arranged into antiferromagnetically exchange-coupled pairs, J=-5.2(6) for 6a and -3.7(4) cm(-1) for 13 (H=-2JS(1)S(2)).

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“…The addition of organometallics to five-membered polyalkoxylated aldonitrones has been amply described to occur with good stereoselectivities. 16 In contrast, the addition of organometallics to six-membered aldonitrones proceeds with lower selectivities 17 and such reactions have never been reported on ketonitrones.…”

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confidence: 93%

Hydroxymethyl-Branched Polyhydroxylated Indolizidines: Novel Selective α-Glucosidase Inhibitors

et al. 2015

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α,α-Disubstituted piperidines and conformationally constrained polyhydroxylated indolizidines bearing a hydroxymethyl substituent in position 8a were synthesized from a readily available l-sorbose-derived ketonitrone. Diastereoselective vinylation under two sets of complementary conditions allowed access to both configurations of the newly formed quaternary stereocenter. Subsequent N-allylation and ring-closing metathesis afforded 8a-branched indolizidines in high yield. The newly prepared iminosugars demonstrated highly potent inhibition of α-glucosidases. Most interestingly, compound 9b exhibits very high selectivity toward this class of enzymes, with an unusual mode of binding.

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New developments in nucleophilic additions to nitrones

Cited by 67 publications

References 41 publications

Synthesis of aza-quaternary centers via Pictet–Spengler reactions of ketonitrones

Synthesis of aza-quaternary centers via Pictet–Spengler reactions of ketonitrones

1,2‐Dihydrotriazinyl‐N‐oxy Free Radicals

Hydroxymethyl-Branched Polyhydroxylated Indolizidines: Novel Selective α-Glucosidase Inhibitors

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