Hypervalent-Iodine-Mediated Base-Free Oxidative Olefination of Benzylic Amines to Access α,β-Unsaturated Ketones

Abstract

We report a one-pot base-free protocol for the oxidative olefination of benzylic amines promoted by a hypervalent iodine reagent for the synthesis of α,β-unsaturated ketones. Mechanistically, (diacetoxyiodo)benzene oxidizes the benzylic amine to the corresponding imine, which, on reaction with a phenacyl(triphenyl)phosphonium bromide salt and an in situ generated acetoxy anion leads to an α,β-unsaturated ketone. A wide range of α,β-unsaturated ketones were easily accessed through direct oxidative olefination of substituted benzylic amines in good to excellent yields and with high E-selectivity.

Key words

hypervalent iodine - benzylic amines - enones - oxidation - olefination

Publikationsverlauf

Eingereicht: 08. Juni 2024

Angenommen nach Revision: 23. Juli 2024

Artikel online veröffentlicht:
22. August 2024

• References and Notes

• 1a Zhuang C, Zhang W, Sheng C, Zhang W, Xing C, Miao Z. Chem. Rev. 2017; 117: 7762
• 1b Wei H, Ruan J, Zhang X. RSC Adv. 2016; 6: 10846
• 1c Nielsen SF, Larsen M, Boesen T, Schønning K, Kromann H. J. Med. Chem. 2005; 48: 2667
• 1d Tatsuzaki J, Bastow KF, Nakagawa-Goto K, Nakamura S, Itokawa H, Lee K.-H. J. Nat. Prod. 2006; 69: 1445
• 1e Tuncel S, Trivella A, Atilla D, Bennis K, Savoie H, Albrieux F, Delort L, Billard H, Dubois V, Ahsen V, Caldefie-Chézet F, Richard C, Boyle RW, Ducki S, Dumoulin F. Mol. Pharmaceutics 2013; 10: 3706
• 1f Kumar SK, Hager E, Pettit C, Gurulingappa H, Davidson NE, Khan SR. J. Med. Chem. 2003; 46: 2813
• 1g Domínguez JN, León C, Rodrigues J, Gamboa de Domínguez N, Gut J, Rosenthal PJ. J. Med. Chem. 2005; 48: 3654
• 1h Prakash G, Boopathy M, Selvam R, John S, Kumar S, Subramanian K. New J. Chem. 2018; 42: 1037
• 1i Wu J, Li J, Cai Y, Pan Y, Ye F, Zhang Y, Zhao Y, Yang S, Li X, Liang G. J. Med. Chem. 2011; 54: 8110
• 1j Quaglio D, Zhdanovskaya N, Tobajas G, Cuartas V, Balducci S, Christodoulou MS, Fabrizi G, Gargantilla M, Priego E.-M, Pestaña ÁC, Passarella D, Screpanti I, Botta B, Palermo R, Mori M, Ghirga F, Pérez-Pérez M.-J. ACS Med. Chem. Lett. 2019; 10: 639
• 1k Rocha S, Sousa A, Ribeiro D, Correia CM, Silva VL. M, Santos CM. M, Silva AM. S, Araújo AN, Fernandes E, Freitas M. Food Funct. 2019; 10: 5510
• 2a Chen H, Noirbent G, Liu S, Brunel D, Graff B, Gigmes D, Zhang Y, Sun K, Morlet-Savary F, Xiao P, Dumur F, Lalevée J. Mater. Chem. Front. 2021; 5: 901
• 2b Almeida LR, Anjos MM, Ribeiro GC, Valverde C, Machado DF. S, Oliveira GR, Napolitano HB, de Oliveira HC. B. New J. Chem. 2017; 41: 1744
• 2c Alvim HG. O, Fagg EL, de Oliveira A, de Oliveira HC. B, Freitas SM, Xavier M.-AE, Soares TA, Gomes AF, Gozzo FC, Silva WA, Brenno AD. Org. Biomol. Chem. 2013; 11: 4764
• 2d Ramaganthan B, Gopiraman M, Olasunkanmi LO, Kabanda MM, Yesudass S, Bahadur I, Adekunle AS, Obote IB, Ebenso EE. RSC Adv. 2015; 5: 76675
• 3a Kane R. Ann. Phys. (Berlin, Ger.) 1838; 44: 475
• 3b Kane R. J. Prakt. Chem. 1838; 15: 129
• 3c Claisen L, Claparède A. Ber. Dtsch. Chem. Ges. 1881; 14: 2460
• 3d Schmidt JG. Ber. Dtsch. Chem. Ges. 1881; 14: 1459
• 4a Adnan D, Singh B, Mehta SK, Kumar V, Kataria R. Curr. Res. Green Sustainable Chem. 2020; 3: 100041
• 4b Kantam ML, Prakash BV, Reddy CV. Synth. Commun. 2005; 35: 1971
• 5a Xue K, Sun G, Zhang Y, Chen X, Zhou Y, Houd J, Long H, Zhang Z, Lei M, Wu W. Synth. Commun. 2021; 51: 625
• 5b Tamuli KJ, Sahoo RK, Bordoloi M. New J. Chem. 2020; 44: 20956
• 5c Gomes C, Vinagreiro CS, Damas L, Aquino G, Quaresma J, Chaves C, Pimenta J, Campos J, Pereira M, Pineiro M. ACS Omega 2020; 5: 10868
• 6a Li L, Stimac JC, Geary LM. Tetrahedron Lett. 2017; 58: 1379
• 6b Li Z, Zhao H, Han H, Liu Y, Song J, Guo W, Chu W, Sun Z. Tetrahedron Lett. 2017; 58: 3984
• 6c Khan K, Siddiqui ZN. Appl. Organomet. Chem. 2014; 28: 789
• 6d Tamuly C, Saikia I, Hazarika M, Bordoloi M, Hussain N, Das MR, Deka K. RSC Adv. 2015; 5: 8604
• 7 Unoh Y, Hirano K, Satoh T, Miura M. J. Org. Chem. 2013; 78: 5096
• 8 Zhang N, Yang D, Wei W, Yuan L, Nie F, Tian L, Wang H. J. Org. Chem. 2015; 80: 3258
• 9 Wei Y, Tang J, Cong X, Zeng X. Green Chem. 2013; 15: 3165
• 10a Rupanawar BD, Veetil SM, Suryavanshi G. Eur. J. Org. Chem. 2019; 6232
• 10b Ramavath V, Rupanawar BD, More SG, Bansode AH, Suryavanshi G. New J. Chem. 2021; 45: 8806
• 11 Bansode AH, Suryavanshi G. RSC Adv. 2018; 8: 32055
• 12 Tangella Y, Manasa KL, Sathish M, Alarifi A, Kamal A. ChemistrySelect 2016; 1: 2895
• 13 Hendrickson JB, Sommer TJ, Singer M. Synthesis 1995; 1496
• 14a Holt HJr, LeBlanc R, Dickson J, Brown T, Maddox JR, Lee M. Heterocycl. Commun. 2005; 11: 465
• 14b Bansode AH, Suryavanshi G. ACS Omega. 2019; 4: 9636
• 14c Liang Y, Dong D, Lu Y, Wang Y, Pan W, Chai Y, Liu Q. Synthesis 2006; 3301
• 14d Mori A, Miyakawa Y, Ohashi E, Haga T, Maegawa T, Sajiki H. Org. Lett. 2006; 8: 3279
• 15 α,β-Unsaturated Ketones 3a–o and 4a–m; General Procedure PhI(OAc)₂ (1.2 mmol) was added to a solution of the appropriate benzylic amine (1.0 mmol) in EtOH (5 mL) at rt. The appropriate phenacyl(triphenyl)phosphonium bromide salt (1.2 mmol) was then added, and the resulting mixture was refluxed at 70 °C for 4 h until the reaction was complete (TLC). Ice was added and the mixture was concentrated under reduced pressure to remove EtOH. CH₂Cl₂ was then added and the reaction was quenched with sat. aq NaHCO₃ (5 mL). The mixture was extracted with CH₂Cl₂ (10 mL), and the organic layers were combined, washed with brine, dried (Na₂SO₄), and concentrated under reduced pressure. The residue was purified by column chromatography [silica gel (100–200 mesh), 5–20% EtOAc–PE]. (2E)-3-(2-Methoxyphenyl)-1-phenylprop-2-en-1-one (3c) White solid; yield: 188 mg (79%); mp 58 °C. ¹H NMR (500 MHz, CDCl₃): δ = 8.13 (d, J = 15.9 Hz, 1 H), 8.05-8.00 (m, 2 H), 7.66-7.61 (m, 2 H), 7.59-7.55 (m, 1 H), 7.50 (ddd, J = 8.3, 6.7, 1.3 Hz, 2 H), 7.38 (ddd, J = 8.3, 7.4, 1.7 Hz, 1 H), 7.00 (td, J = 7.5, 1.0 Hz, 1 H), 6.94 (dd, J = 8.4, 1.0 Hz, 1 H), 3.91 (s, 3 H). ¹³C {¹H} NMR (126 MHz, CDCl₃): δ = 191.2, 158.9, 140.4, 138.6, 132.6, 131.8, 129.3, 128.6, 128.6, 123.9, 122.9, 120.8, 111.3, 55.6. HRMS (ESI): m/z [M + H]⁺ calcd for C₁₆H₁₅O₂: 239.1067; found: 239.1056.