CuCl-catalyzed radical cyclisation of N-α-perchloroacyl-ketene-N,S-acetals: a new way to prepare disubstituted maleic anhydrides

Cornia, Andrea; Felluga, Fulvia; Frenna, Vincenzo; Ghelfi, Franco; Parsons, Andrew F.; Pattarozzi, Mariella; Roncaglia, Fabrizio; Spinelli, Domenico

doi:10.1016/j.tet.2012.04.117

Cited by 17 publications

(11 citation statements)

References 116 publications

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“…The RC of N -α-perchloroacyl-2-( Z )-alkyliden-1,3-thiazinane A was shown to be, by far, the most efficient and selective reaction (Scheme 4). 23 Invariably the catalytic cycle begins with the formation of a carbamoyl methyl radical, which leads to a cascade of reactions, including a radical polar crossover step, culminating in the formation of the maleimide nucleus ( D and E ), or of a direct precursor of it ( E ) (Scheme 4). The typical large prevalence of E over D likely means that the quenching of the acyliminium cation B by C is kinetically favoured in comparison with the oxidative homocoupling of C .…”

Section: Resultsmentioning

confidence: 99%

“…The crude products from this step were then hydrolyzed according to Argade's method, 19c affording the expected anhydrides F in a more than acceptable overall yield from the starting enamides A (Scheme 5). 23b …”

Section: Resultsmentioning

confidence: 99%

“…In addition, the deprotection of the thioacetal group in E (following the method of Hajipour) 26 was exceedingly long (around 2 d) and used a large amount of solid reagents (Scheme 5, step c). 23 …”

Section: Resultsmentioning

confidence: 99%

“…But it was indeed quite clean and was acylated, as such, using 2,2-dichloropropanoyl chloride, affording the N -acyl-ketene- N , S -acetal 10 (a relatively robust molecule, that was purified by chromatography) in high yield (80–90%) (Scheme 6). Because analogues of N -acyl-ketene- N , S- acetals typically have a Z configured C=C bond, 23b the same geometry was assigned to 10 , and to the other enamides we prepared in this work.…”

Section: Resultsmentioning

confidence: 99%

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Novel route to chaetomellic acid A and analogues: Serendipitous discovery of a more competent FTase inhibitor

Bellesia

Choi

Felluga

et al. 2013

Bioorganic & Medicinal Chemistry

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A new practical route to chaetomellic acid A (ACA), based on the copper catalysed radical cyclization (RC) of (Z)-3-(2,2-dichloropropanoyl)-2-pentadecylidene-1,3-thiazinane, is described. Remarkably, the process entailed: i) a one-pot preparation of the intermediate N-α-perchloroacyl-2-(Z)-alkyliden-1,3-thiazinanes starting from N-(3-hydroxypropyl)palmitamide, ii) a two step smooth transformation of the RC products into ACA and iii) only one intermediate chromatographic purification step. The method offers a versatile approach to the preparation of ACA analogues, through the synthesis of an intermediate maleic anhydride with a vinylic group at the end of the aliphatic tail, a function that can be transformed through a thiol-ene coupling. Serendipitously, the disodium salt of 2-(9-(butylthio)nonyl)-3-methylmaleic acid, that we prepared as a representative sulfurated ACA analogue, was a more competent FTase inhibitor than ACA. This behaviour was analysed by a molecular docking study.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Novel route to chaetomellic acid A and analogues: Serendipitous discovery of a more competent FTase inhibitor

Bellesia

Choi

Felluga

et al. 2013

Bioorganic & Medicinal Chemistry

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“…General and productive synthetic protocols achieving γ‐lactams have also been developed looking at the alternative 5‐endo‐trig cyclization of αC‐centered radicals generated from N ‐vinyl‐α‐haloamides, otherwise named α‐haloenamides –. In 2001, this topic has been authoritatively reviewed by Pearsons while more recently a short review on the radical cyclization of trichloroacetamides to lactams has appeared in the literature .…”

Section: Intramolecular α‐Alkylation Of α‐Haloamides: Syntheses Of γ‐mentioning

confidence: 99%

The Fascinating Chemistry of α‐Haloamides

et al. 2020

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The aim of this review is to highlight the rich chemistry of α‐haloamides originally mainly used to discover new C−N, C−O and C−S bond forming reactions, and later widely employed in C−C cross‐coupling reactions with C(sp3), C(sp2) and C(sp) coupling partners. Radical‐mediated transformations of α‐haloamides bearing a suitable located unsaturated bond has proven to be a straightforward alternative to access diverse cyclic compounds by means of either radical initiators, transition metal redox catalysis or visible light photoredox catalysis. On the other hand, cycloadditions with α‐halohydroxamate‐based azaoxyallyl cations have garnered significant attention. Moreover, in view of the important role in life and materials science of difluoroalkylated compounds, a wide range of catalysts has been developed for the efficient incorporation of difluoroacetamido moieties into activated as well as unactivated substrates.

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Efficient and Green Route to γ‐Lactams by Copper‐Catalysed Reversed Atom Transfer Radical Cyclisation of α‐Polychloro‐N‐allylamides, using a Low Load of Metal (0.5 mol%)

et al. 2013

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The cyclisation of N-allyl-N-substituteda-\ud polychloroamides is efficiently obtained through\ud a copper-catalysed activators regenerated by electron\ud transfer–atom transfer radical cyclisation process,\ud with a metal load of only 0.5 mol%. The redox\ud catalyst is introduced in its inactive form as copper(\ud II) chloride/[nitrogen ligand] complex, and continuously\ud regenerated to the active copper(I) chloride/[\ud nitrogen ligand] species by ascorbic acid. To\ud preserve the catalyst integrity, the hydrochloric\ud acid, released after each regeneration cycle, has\ud been quenched by carbonate. The choice of the solvent\ud is critical, the best performance being observed\ud in ethyl acetate-ethanol (3:1)

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CuCl-catalyzed radical cyclisation of N-α-perchloroacyl-ketene-N,S-acetals: a new way to prepare disubstituted maleic anhydrides

Cited by 17 publications

References 116 publications

Novel route to chaetomellic acid A and analogues: Serendipitous discovery of a more competent FTase inhibitor

Novel route to chaetomellic acid A and analogues: Serendipitous discovery of a more competent FTase inhibitor

The Fascinating Chemistry of α‐Haloamides

Efficient and Green Route to γ‐Lactams by Copper‐Catalysed Reversed Atom Transfer Radical Cyclisation of α‐Polychloro‐N‐allylamides, using a Low Load of Metal (0.5 mol%)

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