K. Mollet

Reactivity of 3-oxo-β-lactams with respect to primary amines - an experimental and computational approach

N. Piens, H. Goossens, D. Hertsen, S. Deketelaere, L. Crul, L. Demeurisse, J. De Moor, E. Van den Broeck, K. Mollet, K. Van Hecke, V. Van Speybroeck, M. D'Hooghe
Chemistry - A European Journal
2017 (23), 1-9
2017
A1

Abstract 

The reactivity of 3-oxo-β-lactams with respect to primary amines was investigated in depth. Depending on the specific azetidin-2-one C4 substituent, this reaction was shown to selectively produce 3-imino-β-lactams (through dehydration), α-aminoamides (through CO elimination) or ethanediamides (through an unprecedented C3-C4 ring opening). In addition to the experimental results, the mechanisms and factors governing these peculiar transformations were also examined and elucidated by means of density functional theory calculations.

Synthesis of 2-Hydroxy-1,4-oxazin-3-ones through Ring Transformation of 3-Hydroxy-4-(1,2-dihydroxyethyl)--lactams and a Study of Their Reactivity

K. Mollet, H. Goossens, N. Piens, S. Catak, M. Waroquier, V. Van Speybroeck, M. D'Hooghe, N. De Kimpe
Chemistry - A European Journal
19 (10), 3383-3396
2013
A1

Abstract 

The reactivity of 3-hydroxy-4-(1,2-dihydroxyethyl)-β-lactams with regard to the oxidant sodium periodate was evaluated, unexpectedly resulting in the exclusive formation of new 2-hydroxy-1,4-oxazin-3-ones through a C3C4 bond cleavage of the intermediate 4-formyl-3-hydroxy-β-lactams followed by a ring expansion. This peculiar transformation stands in sharp contrast with the known NaIO4-mediated oxidation of 3-alkoxy- and 3-phenoxy-4-(1,2-dihydroxyethyl)-β-lactams, which exclusively leads to the corresponding 4-formyl-β-lactams without a subsequent ring enlargement. In addition, this new class of functionalized oxazin-3-ones was further evaluated for its potential use as building blocks in the synthesis of a variety of differently substituted oxazin-3-ones, morpholin-3-ones and pyrazinones. Furthermore, additional insights into the mechanism and the factors governing this new ring-expansion reaction were provided by means of density functional theory calculations.

Stereoselective synthesis of cis-3,4-disubstituted piperidines through ring transformation of 2-(2-mesyloxyethyl)azetidines

K. Mollet, S. Catak, M. Waroquier, V. Van Speybroeck, M. D'Hooghe, N. De Kimpe
Journal of Organic Chemistry
76 (20), 8364–8375
2011
A1

Abstract 

The reactivity of 2-(2-mesyloxyethyl)azetidines, obtained through monochloroalane reduction and mesylation of the corresponding β-lactams, with regard to different nucleophiles was evaluated for the first time, resulting in the stereoselective preparation of a variety of new 4-acetoxy-, 4-hydroxy-, 4-bromo-, and 4-formyloxypiperidines. During these reactions, transient 1-azoniabicyclo[2.2.0]hexanes were prone to undergo an SN2-type ring opening to afford the final azaheterocycles, which was rationalized by means of a detailed computational analysis. This approach constitutes a convenient alternative for the known preparation of 3,4-disubstituted 5,5-dimethylpiperidines, providing an easy access to the 5,5-nor-dimethyl analogues as valuable templates in medicinal chemistry. Furthermore, cis-4-bromo-3-(phenoxy or benzyloxy)piperidines were elaborated into the piperidin-3-one framework via dehydrobromination followed by acid hydrolysis.

Synthesis of 2-hydroxy-1,4-oxazin-3-ones through ring transformation of 3-hydroxy-4-(1,2-dihydroxyethyl)-β-lactams and study of their reactivity

ISBN/ISSN:
Talk

Conference / event / venue 

12th Chemistry Conference for Young Scientists
Blankenberge, Belgium
Thursday, 27 February, 2014 to Friday, 28 February, 2014

Synthesis of 2-hydroxy-1,4-oxazin-3-ones through ring transformation of 3-hydroxy-4-(1,2-dihydroxyethyl)-β-lactams and study of their reactivity

ISBN/ISSN:
Talk

Conference / event / venue 

17th Sigma-Aldrich Organic Synthesis Meeting
Blankenberge, Belgium
Thursday, 5 December, 2013 to Friday, 6 December, 2013
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