Asymmetric synthesis of α,β-substituted β-aminoalkanamides and stereochemical determination

doi:10.1016/j.tetlet.2007.10.035

Tetrahedron Letters

Volume 48, Issue 49, 3 December 2007, Pages 8655-8658

https://doi.org/10.1016/j.tetlet.2007.10.035 Get rights and content

Abstract

Highly enantiomerically enriched β-aminoalkanamides 12 and β-phenylaminoalkanamides 13 have been prepared by the addition reaction of α-lithiated 2-alkyl-2-oxazolines 9-Li, derived from optically active oxazolines 9, to N-cumyl nitrones 2. The relative stereochemistry of alkanamides 5 and 6 has been established by 1D-NOESY experiments carried out on the related pyrimidinones 7, whereas the absolute configuration of alkanamides 12 and 13 has been confirmed by an X-ray analysis.

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Acknowledgements

This work was carried out under the framework of the National Project ‘Stereoselezione in Sintesi Organica. Metodologie ed Applicazioni’ and financially supported by MIUR and the University of Bari.

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Chapter 5.7: Five-membered ring systems with O & N atoms
2009, Progress in Heterocyclic Chemistry
Citation Excerpt :
α-Lithiation of 2-alkyloxazolines 141 followed by reaction with aliphatic, aromatic, and heteroaromatic N-cumyl nitrones 142 led to 1,6-dioxa-2,9-diazaspiro[4,4]nonanes 143 which equilibrate with the ring-opened hydroxylamino isomers 144; such equilibration mixtures can be easily transformed into β-amino amides 145 under reductive conditions and β-phenylamino amides 146 under acidic hydrolysis via a cumene hydroperoxide-type rearrangement <07TL8651>. Highly enantiomerically enriched 145 and 146 were prepared starting from optically active oxazolines <07TL8655>. A practical synthesis of acylated glycosyl isothiocyanates from N-glycooxazolines by reaction with thiophosgene has been reported.
This chapter provides an overview of five-membered ring systems with O and N atoms. The chapter discusses (1) isoxazoles, (2) isoxazolines, (3) isoxazolidines, (4) oxazoles, (5) oxazolines, (6) oxazolidines, and (7) oxadiazoles. The importance of 1,3-dipolar cycloadditions (1,3-DC) in the realm of heterocyclic synthesis is widely studied and recent results concerning the intramolecular version of this methodology, including reactions with nitrile oxides and nitrones for access to isoxazole derivatives, are reviewed in the chapter. An efficient solid-phase synthesis of 3,5-disubstituted isoxazoles using polymer-supported selenium resin has been developed with the aim of reducing many side reactions, including dimerization, involved in 1,3-DC of nitrile oxides in solution. A fast and efficient bromination of isoxazoles has been reported using N-bromosuccinimide in different acidic solvents under microwave irradiation. Chloramine-T and silica gel in ethanol are successfully used to generate nitrile oxides from sugar-derived oximes in the presence of unmasked hydroxyl groups. This method is applied to the synthesis of bi- and tri-cyclic isoxazolines by intramolecular nitrile oxide–alkene cycloaddition (INOC).
Asymmetric Synthesis of Six-Membered Ring Nitrogen Heterocycles with More Than One Heteroatom
2009, Asymmetric Synthesis of Nitrogen Heterocycles
Crystal structure of (+)-(2S,3S,1′5)-2-ethyl-N-(1-hydroxymethyl-2- methylpropyl)-2-methyl-3-phenyl-3-phenylaminopropanamide, C<inf>23</inf>H <inf>32</inf>N<inf>2</inf>O<inf>2</inf>
2008, Zeitschrift fur Kristallographie - New Crystal Structures
Crystal structure of (2R*, 3R*)-3-amino-2-ethyl-N-(2-hydroxy-1, 1-dimethylethyl)-3-p-methoxyphenylpropanamide, C<inf>17</inf>H <inf>28</inf>N<inf>2</inf>O<inf>3</inf>
2008, Zeitschrift fur Kristallographie - New Crystal Structures

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Tetrahedron Letters

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Acknowledgements

References and notes (11)

Tetrahedron

Tetrahedron

Bull. Chem. Soc. Fr.

J. Org. Chem.

Cited by (4)

Chapter 5.7: Five-membered ring systems with O & N atoms

Asymmetric Synthesis of Six-Membered Ring Nitrogen Heterocycles with More Than One Heteroatom

Crystal structure of (+)-(2S,3S,1′5)-2-ethyl-N-(1-hydroxymethyl-2- methylpropyl)-2-methyl-3-phenyl-3-phenylaminopropanamide, C<inf>23</inf>H <inf>32</inf>N<inf>2</inf>O<inf>2</inf>

Crystal structure of (2R, 3R)-3-amino-2-ethyl-N-(2-hydroxy-1, 1-dimethylethyl)-3-p-methoxyphenylpropanamide, C<inf>17</inf>H <inf>28</inf>N<inf>2</inf>O<inf>3</inf>