Diastereoselective Synthesis of Pyrazolines by Metal-Free Rearrangement of Bicyclic Triazolines

Abstract

The metal-free preparation of diazoalkanes through the ring rearrangement of bicyclic triazolines is reported here. Their use in 1,3-dipolar cycloaddition reactions with electron-withdrawing alkenes was investigated. This synthetic procedure allows differently substituted pyrazolines to be obtained in few steps and with high atom economy.

Key words

diazoalkanes - pyrazolines - amidines - 1,3-dipolar cycloaddition - triazoline rearrangement - metal-free reactions - diastereoselectivity - atom economy

• References

• 1a Zhang Y, Zheng X, Zhang L, Yang Z, Chen L, Wang L, Liu S, Xie Z. Org. Biomol. Chem. 2020; 18: 707
• 1b Locarno S, Eleta-Lopez A, Lupo MG, Gelmi ML, Clerici F, Bittner AM. RSC Adv. 2019; 9: 20565
• 1c Varghese B, Al-Busafi SN, Suliman FO, Al-Kindya SM. Z. RSC Adv. 2017; 7: 46999
• 1d Faria JV, Fazolin VP, Carvalho MA. G, dos Santos MS, Boechat N, Bernardino RA. M. Bioorg. Med. Chem. 2017; 25: 5891
• 1e Korablina DD, Vorozhtsov NI, Sviridova LA, Kalenikova EI, Medvedev OS. Pharm. Chem. J. 2016; 50: 281
• 1f Havrylyuk D, Roman A, Lesyk R. Eur. J. Med. Chem. 2016; 145
• 2a Lellek V, Chen C, Yang W, Ji JL. X. Synlett 2018; 29: 1071
• 2b Alex K, Tillack A, Schwarz N, Beller M, Faesslera R. Org. Lett. 2008; 2377
• 2c Fustero S, Simon-Fuentes A, Sanz-Cervera JF. Org. Prep. Proced. Int. 2009; 41: 253
• 3a Nájera C, Sansano JM, Yus M. Org. Biomol. Chem. 2015; 13: 8596
• 3b Lévai A. J. Heterocycl. Chem. 2002; 39: 1
• 4 Fegheh-Hassanpour Y, Ebrahim F, Arif T, Sintim HO, Claridge TD. W, Amin NT, Hodgson DM. Org. Biomol. Chem. 2018; 16: 2876
• 5 Aronoff MR, Gold B, Raines RT. Org. Lett. 2016; 18: 1538
• 6 Regitz M. Diazo Compounds: Properties and Synthesis. Elsevier; Philadelphia: 2012
• 7 Barluenga J, Quiñones N, Tomás-Gamasa M, Cabal MP. Eur. J. Org. Chem. 2012; 2312
• 8 Liu Z, Li Q, Liao P, Bi X. Chem. Eur. J. 2017; 23: 4756
• 9 Furrow ME, Myers AG. J. Am. Chem. Soc. 2004; 126: 12222
• 10 Allouche EM. D, Charette AB. Chem. Sci. 2019; 10: 3802
• 11 Javed MI, Brewer M. Org. Lett. 2007; 9: 1789
• 12 Contini A, Erba E, Pellegrino S. Synlett 2012; 23: 1523
• 13 Bucci R, Dapiaggi F, Macut H, Pieraccini S, Sironi M, Gelmi ML, Erba E, Pellegrino S. Amino Acids 2020; 52: 15