Synlett 2017; 28(04): 494-498
DOI: 10.1055/s-0036-1588331
letter
© Georg Thieme Verlag Stuttgart · New York

Oxidant-Triggered C1-Benzylation of Isoquinoline by Iodine-­Catalyzed Cross-Dehydrogenative-Coupling with Methylarenes

Xin Shi
a   Key Laboratory for Environmentally Friendly Chemistry and Application of the Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, P. R. of China   Email: yangluo@xtu.edu.cn   Email: zhangf@iccas.ac.cn
,
Feng Zhang
b   College of Science, Hunan Agricultural University, Hunan 410128, P. R. of China
,
Wen-Kun Luo
a   Key Laboratory for Environmentally Friendly Chemistry and Application of the Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, P. R. of China   Email: yangluo@xtu.edu.cn   Email: zhangf@iccas.ac.cn
,
Luo Yang*
a   Key Laboratory for Environmentally Friendly Chemistry and Application of the Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan, Hunan 411105, P. R. of China   Email: yangluo@xtu.edu.cn   Email: zhangf@iccas.ac.cn
› Author Affiliations
Further Information

Publication History

Received: 06 August 2016

Accepted after revision: 19 September 2016

Publication Date:
07 November 2016 (online)


Abstract

A practical iodine-catalyzed oxidative functionalization of isoquinolines with methylarenes is developed, which can be triggered by the selected oxidants to produce C1- or N-benzyl-substituted products selectively. This method utilizes readily available isoquinolines and methylarenes as starting materials and proceeds under metal-free conditions with broad substrate scope with respect to methylarenes, avoiding the usage of expensive metal catalysts and generation of halide and metal wastes.

Supporting Information

 
  • References and Notes

  • 2 Hagel JM, Facchini PJ. Plant Cell Physiol. 2013; 54: 647

    • For reviews on Minisci reaction, see:
    • 3a McCallum T, Jouanno L.-A, Cannillo A, Barriault L. Synlett 2016; 27: 1282
    • 3b Tauber J, Imbr D, Opatz T. Molecules 2014; 19: 16190
    • 3c Duncton MA. J. Med. Chem. Commun. 2011; 2: 1135
    • 3d Punta C, Minisci F. Trends Heterocycl. Chem. 2008; 13: 1

      For recent examples on Minisci-type alkylation of heterocycles with functionalized starting materials as radical sources, see:
    • 4a Daniel GM. S, Kimberly AW, Joseph PL, Anthony AE. Tetrahedron Lett. 2015; 56: 4063
    • 4b DiRocco DA, Dykstra K, Krska S, Vachal P, Conway DV, Tudge M. Angew. Chem. Int. Ed. 2014; 53: 4802
    • 4c Bohman B, Berntsson B, Dixon RC. M, Stewart CD, Barrow RA. Org. Lett. 2014; 16: 2787
    • 4d Xia R, Xie M.-S, Niu H.-Y, Qu G.-R, Guo H.-M. Org. Lett. 2014; 16: 444
    • 4e Leverrier A, Bero J, Frederich M, Quetin-Leclercq J, Palermo J. Eur. J. Med. Chem. 2013; 66: 355
    • 4f Duncton MA. J, Estiarte MA, Johnson RJ, Cox M, O’Mahony DJ. R, Edwards WT, Kelly MG. J. Org. Chem. 2009; 74: 6354

      For Minisci-type alkylation of heterocycles with C(sp 3)–H bonds as radical sources, see:
    • 5a Devariab S, Shah BA. Chem. Commun. 2016; 52: 1490
    • 5b Jin J, MacMillan DW. C. Angew. Chem. Int. Ed. 2015; 54: 1565
    • 5c Antonchick AP, Burgmann L. Angew. Chem. Int. Ed. 2013; 52: 3267
    • 5d Wu Z, Pi C, Cui X, Bai J, Wu Y. Adv. Synth. Catal. 2013; 355: 1971
    • 5e Li X, Wang H.-Y, Shi Z.-J. New J. Chem. 2013; 37: 1704
    • 5f Correia CA, Yang L, Li C.-J. Org. Lett. 2011; 13: 4581
    • 5g Deng G, Ueda K, Yanagisawa S, Itami K, Li C.-J. Chem. Eur. J. 2009; 15: 333
    • 5h Deng G, Li C.-J. Org. Lett. 2009; 11: 1171
    • 6a Wan M, Lou H, Liu L. Chem. Commun. 2015; 51: 13953
    • 6b Chen J, Wan M, Hua J, Sun Y, Lv Z, Li W, Liu L. Org. Biomol. Chem. 2015; 13: 11561
  • 7 Wencel-Delord J, Glorius F. Nat. Chem. 2013; 5: 369
    • 8a Tang R.-J, Kang L, Yang L. Adv. Synth. Catal. 2015; 357: 2055
    • 8b Paul S, Guin J. Chem. Eur. J. 2015; 21: 17618
    • 9a Dandia A, Gupta SL, Maheshwari S. Molecular Iodine: Mild, Green, and Nontoxic Lewis Acid Catalyst for the Synthesis of Heterocyclic Compounds. In Green Chemistry: Synthesis of Bioactive Heterocycles. Ameta KL, Dandia A. Springer; India: 2014. Chap. 10
    • 9b Zi Y, Cai Z.-J, Wang S.-Y, Ji S.-J. Org. Lett. 2014; 16: 3094
    • 9c Liu D, Lei A. Chem. Asian J. 2015; 10: 806
    • 9d Zhao J.-J, Gao W.-C, Chang H.-H, Li X, Liu Q, Wei W.-L. Chin. J. Org. Chem. 2014; 34: 1941
    • 10a Luo W.-K, Shi X, Zhou W, Yang L. Org. Lett. 2016; 18: 2036
    • 10b Yang L, Shi X, Hu B.-Q, Wang L.-X. Asian J. Org. Chem. 2016; 5: 494
    • 10c Gao X, Zhang F, Deng G, Yang L. Org. Lett. 2014; 16: 3664
    • 10d Wang F.-F, Luo C.-P, Deng G, Yang L. Green Chem. 2014; 16: 2428
    • 10e Wang F.-F, Luo C.-P, Wang Y, Deng G, Yang L. Org. Biomol. Chem. 2012; 10: 8605
  • 11 A general experimental procedure for this CDC is described as following: an oven-dried reaction vessel was charged with isoquinoline (1a, 0.4 mmol, 1 equiv), I2 (0.02 mmol, 5.2 mg, 5 mol%), DTBP (di-tert-butyl peroxide, 1.2 mmol, 3 equiv) in p-xylene (1 mL) under air. The vessel was sealed and heated at 130 °C for 12 h, then cooled to r.t. The resulting mixture was transferred to a silica gel column and eluted with hexanes and EtOAc (12:1) to give 1-(4-methylbenzyl)isoquinoline (3a) in 71% yield as a yellow oil. 1H NMR (400 MHz, CDCl3): δ = 8.49 (d, J = 5.6 Hz, 1 H), 8.15 (d, J = 8.0 Hz, 1 H), 7.80 (d, J = 8.0 Hz, 1 H), 7.62 (t, J = 7.4 Hz, 1 H), 7.50–7.55 (m, 2 H), 7.17 (d, J = 7.3 Hz, 2 H), 7.05 (d, J = 7.4 Hz, 2 H), 4.63 (s, 2 H), 2.27 (s, 3 H). 13C NMR (100 MHz, CDCl3): δ = 160.48, 142.11, 136.67, 136.49, 135.81, 129.88, 129.30, 128.59, 127.41, 127.28, 127.25, 125.94, 119.82, 41.76, 21.07.