Nitrone cycloaddition. A route to the lupin class of alkaloids

Tufariello, Joseph J.; Tegeler, John J.

doi:10.1016/s0040-4039(00)92569-3

Cited by 43 publications

(6 citation statements)

References 13 publications

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“…The required chiral dipolarophiles 9 and 10 were prepared in good yields by condensation of the aldehyde 11 [12] either with the ylide generated in situ from the triphenylphosphonium bromide 12, or with dimethylphosphonoacetate 13, respectively (Scheme 3). The THP (tetrahydropyranyl) protecting group was replaced by the Ms (methanesulfonyl) group by treatment with Amberlyst ® 15 in methanol, followed by mesylation (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of (7R,8R,8aR)- and (7S,8S,8aS)-7-Hydroxy-8-indolizidinemethanol by 1,3-Dipolar Cycloaddition of 1-PyrrolineN-Oxide to Chiral Pentenoates

et al. 2000

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Section: Resultsmentioning

confidence: 99%

Enantioselective Synthesis of (7R,8R,8aR)- and (7S,8S,8aS)-7-Hydroxy-8-indolizidinemethanol by 1,3-Dipolar Cycloaddition of 1-PyrrolineN-Oxide to Chiral Pentenoates

et al. 2000

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“…Elaboration of the adduct 6 according to Tufariello [4b,14] gave the diprotected triol 7, which eventually furnished the alkaloid 4 by radical deoxygenation and deprotection (Scheme 2). Both procedures also allowed access to 7-hydroxylentiginosines 8 and 9 by appropriate elaboration of 3 and 7, respectively (Scheme 3) [13,6c].…”

Section: Resultsmentioning

confidence: 99%

A Straightforward Route to Enantiopure Pyrrolizidines and Indolizidines by Cycloaddition to Pyrroline N-Oxides Derived from the Chiral Pool

et al. 1998

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Enantiomerically pure, five membered cyclic nitrones, easily obtained in large amounts from protected hydroxyacids and aminoacids such as D-and L-tartaric, L-malic, and L-aspartic acids, give cycloaddition reactions with a good diastereocontrol. The adducts of L-malic and L-aspartic acids derived from addition of nitrones to dimethyl maleate and γ-crotonolactone were easily converted into enantiopure pyrrolizidinones, which can be transformed into polyhydroxypyrrolidines or polyhydroxypyrrolizidines, both interesting compounds as potential glycosidase inhibitors. The method is suitable for natural products synthesis as exemplified by a straightforward and convenient access to the pyrrolizidine alkaloid necine base (-)-hastanecine, as well as to indolizidine alkaloids, i.e. (+)-lentiginosine.

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“…The main component was isolated from the mixture using preparative HPLC. Non-polar character of the products allowed us to discard quaternary alkoxyammonium salt structure, which could be a result of intramolecular alkylation on alkoxyamine nitrogen in analogy to literature [ 24 , 25 , 26 ]. IR and NMR spectra allowed us to identify one of the isolated products as 2 (preparative yield about 13%) .…”

Section: Resultsmentioning

confidence: 99%

The Reactions of 6-(Hydroxymethyl)-2,2-dimethyl-1-azaspiro[4.4]nonanes with Methanesulfonyl Chloride or PPh3-CBr4

et al. 2021

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Activation of a hydroxyl group towards nucleophilic substitution via reaction with methanesulfonyl chloride or PPh3-CBr4 system is a commonly used pathway to various functional derivatives. The reactions of (5R(S),6R(S))-1-X-6-(hydroxymethyl)-2,2-dimethyl- 1-azaspiro[4.4]nonanes 1a–d (Х = O·; H; OBn, OBz) with MsCl/NR3 or PPh3-CBr4 were studied. Depending on substituent X, the reaction afforded hexahydro-1H,6H-cyclopenta[c]pyrrolo[1,2-b]isoxazole (2) (for X = O), a mixture of 2 and octahydrocyclopenta[c]azepines (4–6) (for X = OBn, OBz), or perhydro-cyclopenta[2,3]azeto[1,2-a]pyrrol (3) (for X = H) derivatives. Alkylation of the latter with MeI with subsequent Hofmann elimination afforded 2,3,3-trimethyl-1,2,3,4,5,7,8,8a-octahydrocyclopenta[c]azepine with 56% yield.

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Nitrone cycloaddition. A route to the lupin class of alkaloids

Cited by 43 publications

References 13 publications

Enantioselective Synthesis of (7R,8R,8aR)- and (7S,8S,8aS)-7-Hydroxy-8-indolizidinemethanol by 1,3-Dipolar Cycloaddition of 1-PyrrolineN-Oxide to Chiral Pentenoates

Enantioselective Synthesis of (7R,8R,8aR)- and (7S,8S,8aS)-7-Hydroxy-8-indolizidinemethanol by 1,3-Dipolar Cycloaddition of 1-PyrrolineN-Oxide to Chiral Pentenoates

A Straightforward Route to Enantiopure Pyrrolizidines and Indolizidines by Cycloaddition to Pyrroline N-Oxides Derived from the Chiral Pool

The Reactions of 6-(Hydroxymethyl)-2,2-dimethyl-1-azaspiro[4.4]nonanes with Methanesulfonyl Chloride or PPh3-CBr4

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