Synlett 2016; 27(01): 151-155
DOI: 10.1055/s-0035-1560583
letter
© Georg Thieme Verlag Stuttgart · New York

Tertiary Amine Promoted Aziridination: Preparation of NH-Aziridines from Aliphatic α,β-Unsaturated Ketones

Alan Armstrong*
a   Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK   Email: a.armstrong@imperial.ac.uk
,
Robert D. C. Pullin
a   Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK   Email: a.armstrong@imperial.ac.uk
,
James N. Scutt
b   Syngenta Ltd., Jealott’s Hill International Research Centre, Bracknell, Berkshire, RG42 6EY, UK
› Author Affiliations
Further Information

Publication History

Received: 02 October 2015

Accepted after revision: 09 October 2015

Publication Date:
03 November 2015 (online)


Dedicated to Professor Steven V. Ley on the occasion of his 70th birthday

Abstract

trans-NH-Aziridines were prepared from aliphatic α,β-unsaturated ketones using a tertiary amine promoted reaction via in situ generated N,N-ylides. Through use of modified conditions the reaction proved to be applicable for the diastereoselective aziridination of a range of enolisable aliphatic α,β-unsaturated ketones of varying substitution patterns.

Supporting Information

 
  • References and Notes

  • 1 Current address: Dr. R. D. C. Pullin, Vertex Pharmaceuticals (Europe) Ltd., 86-88 Jubilee Avenue, Milton Park, Abingdon, Oxfordshire, OX14 4RW, UK.
  • 2 For a review, see: Lowden PA. S. In Aziridines and Epoxides in Organic Synthesis . Yudin AK. Wiley-VCH; Weinheim: 2006: 399

    • Isolated examples have been reported, examples include:
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    • 8c Chen D, Timmons C, Guo L, Xu X, Li G. Synthesis 2004; 2479
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  • 13 Armstrong A, Carbery DR, Lamont SG, Pape AR, Wincewicz R. Synlett 2006; 2504
  • 16 Diastereoselectivity determined to be >95:5 by 1H NMR spectroscopy. The cis and trans diastereoselectivity was determined by analysis of the 3 J coupling constants of the aziridine ring; generally trans-aziridines have 3 J = 2–4 Hz, cis-aziridines 3 J = 5–9 Hz. All aziridines prepared were determined be a single dia­stereoisomer.
  • 17 Fioravanti S, Mascia MG, Pellacani L, Tardella PA. Tetrahedron 2004; 60: 8073
  • 18 Menjo Y, Hamajima A, Sasaki N, Hamada Y. Org. Lett. 2011; 13: 5744
  • 20 Aziridine 4e was resubmitted to the reaction conditions in place of the enone substrate and was recovered in quantitative amounts.
  • 21 Representative Procedure for Enone Aziridination N-Methylmorpholine (14 μL, 0.125 mmol) was added dropwise to a solution of DppONH2 (56.0 mg, 0.24 mmol) in CH2Cl2 (2 mL) at r.t., and the mixture was stirred for 0.5 h. i-PrOH (28 μL, 0.36 mmol) and NaH (60% dispersion in mineral oil, 14.4 mg, 0.36 mmol) were then added sequentially followed by addition of trans-4-phenylbut-3-en-2-one (3a, 17.5 mg, 0.12 mmol) in CH2Cl2 (1 mL) and the mixture allowed to stir at r.t. for 16 h. The reaction was quenched by the addition of sat. aq NH4Cl solution and the aqueous layer separated and extracted with CH2Cl2, dried (Na2SO4), filtered and concentrated in vacuo. Purification by flash column chromatography (15% EtOAc–n-hexane) afforded (2R*,3S*)-1-(3-phenylaziridin-2-yl)ethanone (4a, 15.6 mg, 80%) as a colourless oil; Rf = 0.30 (15% EtOAc–n-hexane). 1H NMR (400 MHz, CDCl3): δ = 7.38–7.27 (5 H, m, 5 × PhH), 3.04 (1 H, d, J = 2.0 Hz, 3-CHN), 2.86 (1 H, d, J = 2.1 Hz, 2-CHN), 2.38 (3 H, s, CH3), 2.29 (1 H, br, NH). 13C NMR (100 MHz, CDCl3): δ = 204.5, 138.2, 128.5, 127.8, 126.1, 46.8, 43.0, 29.6.