Synlett 2019; 30(18): 2077-2080
DOI: 10.1055/s-0039-1690704
letter
© Georg Thieme Verlag Stuttgart · New York

Diethyl Phosphite Promoted Electrochemical Oxidation of Tetrahydroisoquinolines to 3,4-Dihydroisoquinolin-1(2H)-ones

Wenxia Xie
,
Bowen Gong
,
Shulin Ning
,
Nian Liu
,
Zhuoqi Zhang
,
Xin Che
,
Lianyou Zheng
,
Jinbao Xiang
This work was supported by the Education Department of Jilin Province (No. JJKH20180244KJ), the Jilin Scientific and Technological Development Program (No. 20160520039JH), and Jilin University (No. 2015330). Additional support was provided by Changchun Discovery Sciences, Ltd.
Further Information

Publication History

Received: 26 August 2019

Accepted after revision: 19 September 2019

Publication Date:
09 October 2019 (online)


Abstract

A diethyl phosphite mediated electrochemical oxidation strategy for the synthesis of 3,4-dihydroisoquinolin-1(2H)-ones from tetrahydroisoquinolines under mild conditions has been developed. This protocol provides an environmentally friendly and simple way for the construction of C=O bonds in an undivided cell unit.

Supporting Information

 
  • References and Notes

  • 1 Chrzanowska M, Rozwadowska MD. Chem. Rev. 2004; 104: 3341
    • 2a Krane BD, Shamma M. J. Nat. Prod. 1982; 45: 377
    • 2b Pettit GR, Meng Y, Herald DL, Graham KA. N, Pettit RK, Doubek DL. J. Nat. Prod. 2003; 66: 1065
    • 2c Fatima N, Reddy BV. S. Sabitha G, Yadav JS, Sudhakar K, Putta CS. Bioorg. Med. Chem. Lett. 2018; 28: 196
  • 3 Chen Z.-Y, Wu L.-Y, Fang H.-S, Zhang T, Mao Z.-F, Zou Y, Zhang X.-J, Yang M. Adv. Synth. Catal. 2017; 359: 3894
    • 4a Han W, Mayer P, Ofial AR. Adv. Synth. Catal. 2010; 352: 1667
    • 4b Kohls P, Jadhav D, Pandey G, Reiser O. Org. Lett. 2012; 14: 672
    • 4c Liu Y, Wang C, Xue D, Xiao M, Liu J, Li C, Xiao J. Chem. Eur. J. 2017; 23: 3062
    • 4d Patil MR, Dedhia NP, Kapdi AR, Kumar AV. J. Org. Chem. 2018; 83: 4477
    • 5a Zhang Y, Riemer D, Schilling W, Kollmann J, Das S. ACS Catal. 2018; 8: 6659
    • 5b Clark JL, Hill JE, Rettig ID, Beres JJ, Ziniuk R, Ohulchanskyy TY, McCormick TM, Detty MR. Organometallics 2019; 38: 2431
    • 5c Guryev AA, Hahn F, Marschall M, Tsogoeva SB. Chem. Eur. J. 2019; 25: 4062
  • 7 Aganda KC. C, Hong B, Lee A. Adv. Synth. Catal. 2019; 361: 1124
    • 8a Yan M, Kawamata Y, Baran PS. Chem. Rev. 2017; 117: 13230
    • 8b Tang S, Zeng L, Lei A. J. Am. Chem. Soc. 2018; 140: 13128
    • 8c Tang S, Liu Y, Lei A. Chem 2018; 4: 27
  • 9 Li C, Zeng C.-C, Hu L.-M, Yang F.-L, Yoo SJ, Little RD. Electrochim. Acta 2013; 114: 560
  • 10 Xie W, Liu N, Gong B, Ning S, Che X, Cui L, Xiang J. Eur. J. Org. Chem. 2019; 2498
  • 11 2-Phenyl-3,4-dihydroisoquinolin-1(2H)-one (4a); Typical Procedure A 10 mL distillation flask equipped with a magnetic stirring bar was charged with diethyl phosphite (42 mg, 0.3 mmol), wet CH2Cl2 (5.0 mL), 2-phenyl-1,2,3,4-tetrahydroisoquinoline 1a (52 mg, 0.25 mmol), and Et4NOTs (151 mg, 0.5 mmol). The resulting suspension was stirred until complete dissolution was achieved. The flask equipped with graphite rod anode (d = 5 mm) and Pt plate cathode (0.5×0.5 cm). The reaction mixture was stirred and electrolyzed at a constant current of 5 mA at rt for 9 h. The reaction mixture was diluted with CH2Cl2 (15 mL), washed successively with water (10 mL) and brine (10 mL), dried with Na2SO4, and concentrated in vacuo. Purification by flash column chromatography (silica gel, petroleum ether–ethyl acetate 20:1) afforded the desired product 4a 48 mg (86%) as a white solid; mp 119–120 °C. 1H NMR (300 MHz, CDCl3): δ = 8.19–8.14 (m, 1 H), 7.51–7.34 (m, 6 H), 7.29–7.21 (m, 2 H), 4.04–3.97 (m, 2 H), 3.15 (t, J = 6.6 Hz, 2 H). 13C NMR (75 MHz, CDCl3): δ = 162.8, 143.1, 138.3, 132.0, 129.7, 128.9, 128.7, 127.1, 126.9, 126.2, 125.3, 49.4, 28.6.