Subscribe to RSS
Please copy the URL and add it into your RSS Feed Reader.
https://www.thieme-connect.de/rss/thieme/en/10.1055-s-00000083.xml
Synlett 2018; 29(04): 463-466
DOI: 10.1055/s-0036-1589135
DOI: 10.1055/s-0036-1589135
letter
Cu(I)-Catalyzed Synthesis of β,γ-Unsaturated Amides
Financial support of this research by the College of the Holy Cross Summer Research Fellowship Program is gratefully acknowledged.Further Information
Publication History
Received: 31 August 2017
Accepted after revision: 24 October 2017
Publication Date:
22 November 2017 (online)
Abstract
Readily available propargyl alcohols were found to be useful substrates for the copper(I)-catalyzed synthesis of β,γ-unsaturated amides. Nucleophilic attack by the alcohol on the in situ generated ketenimine followed by base-catalyzed elimination and subsequent ring opening yields the desired products under mild conditions.
Supporting Information
- Supporting information for this article is available online at http://doi.org/10.1055/s-0036-1589135.
- Supporting Information
-
References and Notes
- 1 Bae I. Han H. Chang S. J. Am. Chem. Soc. 2005; 127: 2038
- 2 Cassidy MP. Raushel H. Fokin VV. Angew. Chem. Int. Ed. 2007; 46: 1730
- 3a Rostotev VV. Green LG. Fokin VV. Sharpless KB. Angew. Chem. Int. Ed. 2002; 41: 2596
- 3b Tornøe CW. Christensen C. Meldal M. J. Org. Chem. 2002; 67: 3057
- 4a Yoo EJ. Chang S. Curr. Org. Chem. 2009; 11: 1155
- 4b Kim SH. Park S. Choi JH. Chang S. Chem. Asian J. 2011; 6: 2618
- 4c Chen JL. Namirembe S. Lauchert LT. Tsougranis GH. Isaacs AK. Tetrahedron Lett. 2015; 56: 4105
- 5a Chauhan DP. Varma SJ. Vijeta A. Banerjee P. Talukdar P. Chem. Commun. 2014; 50: 323
- 5b Kumar YK. Kumar GR. Reddy MS. J. Org. Chem. 2014; 79: 823
- 5c Wang J. Wang J. Lu P. Wang Y. J. Org. Chem. 2013; 78: 8816
- 6 Yoo EL. Bae I. Cho SH. Han H. Chang S. Org. Lett. 2006; 8: 1347
- 7 Nagaraj M. Boominathan M. Perumal D. Muthusubramanian S. Bhuvanesh N. J. Org. Chem. 2012; 77: 6319
- 8 Bajracharya GB. Koranne PS. Nadaf RN. Gabr RK. Takenaka K. Takizawa S. Sasai H. Chem. Commun. 2010; 46: 9064
- 9 Marson CM. Fallah A. Tetrahedron Lett. 1994; 35: 293
- 10 Smith S. Takacs JM. J. Am. Chem. Soc. 2010; 132: 1740
- 11a Kiss A. Hell Z. Tetrahedron Lett. 2011; 52: 6021
- 11b Lee J. Kim M. Chang S. Lee H. Org. Lett. 2009; 11: 5598
- 12 Das B. Madhusudhan P. Tetrahedron Lett. 1998; 39: 9099
- 13 Cho SH. Yoo EJ. Bae I. Chang S. J. Am. Chem. Soc. 2005; 127: 16046
- 14 To a solution of propargyl alcohol 1a (119 mg, 0.96 mmol, 1.2 equiv) in CH2Cl2 (4.8 mL, 0.2 M) in a 1 dram vial was added tosyl azide (158 mg, 0.8 mmol, 1 equiv), then CuCl (16 mg, 0.16 mmol, 0.2 equiv) followed by Et3N (167 μL, 1.2 mmol, 1.5 equiv). The reaction was allowed to stir at ambient temperature in a block for 12 h at which time TLC analysis indicated complete consumption of the starting material and formation of the β,γ-unsaturated amide. The reaction was filtered through Celite. The solvent was removed in vacuo, and the residue was purified by flash column chromatography (hexanes/ethyl acetate = 5:1) to yield β,γ-unsaturated amide 2a (234 mg, 70%) as a white solid, mp 94–95 °C. The spectral data was in agreement with reported data.13 1H NMR (400 MHz, CDCl3): δ = 8.22 (s, 1 H), 7.93 (d, J = 8.4 Hz, 2 H), 7.33 (d, J = 8.4 Hz, 2 H), 5.61 (s, 1 H), 2.87 (s, 2 H), 2.44 (s, 3 H), 2.03 (m, 2 H), 1.79 (m, 2 H), 1.60–1.52 (m, 4 H). 13C NMR (100 MHz, CDCl3): δ = 168.8, 145.1, 135.4, 131.0, 129.5, 128.6, 128.4, 46.5, 28.1, 25.3, 22.4, 21.7, 21.6.