Platinum-Catalyzed Regioselective Dehydrogenative Homocoupling of Dimethyl Phthalate for the Direct Synthesis of Sym-BPTT

Abstract

A novel synthesis method for sym-BPTT, an important synthetic intermediate for electronic materials, is reported. This method features a platinum-catalyzed regioselective dehydrogenative homocoupling of dimethyl phthalate. Unlike previous palladium-catalyzed methods, this reaction proceeds with high regioselectivity without requiring any ligands when an appropriate reoxidation system is employed, thus simplifying the purification process. While the yield is currently lower than that of existing methods, this study demonstrates the potential of platinum catalysts for dehydrogenative homocoupling reactions. A preliminary continuous-flow system for this homocoupling reaction was also developed, although the yield was low, and regioselectivity was not well-controlled.

Keywords

Platinum catalyst - Dehydrogenative homocoupling - Continuous-flow synthesis

Publication History

Received: 21 October 2024

Accepted after revision: 10 March 2025

Accepted Manuscript online:
12 March 2025

Article published online:
02 April 2025

• References

• 1a Numata S, Oohara S, Fujisaki K, Imaizumi J. Kinjo N. J. Appl. Polym. Sci. 1986; 31: 101
• 1b Saraf RF, Tong H.-M, Poon TW, Silverman BD, Ho PS, Rossi AR. J. Appl. Polym. Sci. 1992; 46: 1329
• 1c Chen ST, Wagner HH. J. Electron. Mater. Lett. 1993; 22: 797
• 1d Hasegawa M, Matano T, Shindo Y, Sugimura T. Macromolecules 1996; 29: 7897
• 2a Ree M, Goh WH, Park J.-W, Lee M.-H, Rhee S.B. Polym. Bull. 1995; 35: 129
• 2b Yue Z, Cai Y.-B, Xu S. J. Polym. Res. I 2014; 21: 463
• 2c Wang Y, Tao L, Wang T, Wang Q. RSC Adv. 2015; 5: 101533
• 2d Ishikawa A, Mitsui H, Tanaka Y, Sasaki K. JP Patent No. 4048689 2007
• 2e Inoue H. Kobunshi 1997; 46: 566
• 3a Kuroboshi M, Waki Y, Tanaka H. Synlett 2002; 4: 637
• 3b Kuroboshi M, Waki Y, Tanaka H. J. Org. Chem. 2003; 68: 3938
• 3c Wu XE, Gao CL, Meng X, Zhang SB, Gao LX. Chin. Chem. Lett. 2004; 15: 787
• 3d Wu X.-L. Huaxue Shiji 2017; 39: 1015
• 4a Itatani H, Yoshimoto H. J. Org. Chem. 1973; 38: 76
• 4b Yoshimoto H, Itatani H. J. Catal. 1973; 31: 8
• 4c Shiotani A, Yoshikiyo M, Itatani H. J. Mol. Catal. 1983; 18: 23
• 4d Shiotani A, Itatani H, Inagaki T. J. Mol. Catal. 1986; 34: 57
• 5 Ishida T, Aikawa S, Mise Y, Akebi R, Hamasaki A, Honma T, Ohashi H, Tsuji T, Yamamoto Y, Miyasaka M, Yokoyama T, Tokunaga M. ChemSusChem 2015; 8: 695
• 6 Yang Y, Lan J, You J. Chem. Rev. 2017; 117: 8787 and references therein
• 7a Zhang X.-W, Shen S.-C, Hidajat K, Kawi S, Yu LE, Simon Ng KY. Catal. Lett. 2004; 96: 1
• 7b Maphoru MV, Heveling J, Pillai SK. Eur. J. Org. Chem. 2016; 331
• 7c Maphhoru MV, Pillai SK, Heveling J. J. Catal. 2017; 348: 47
• 7d Matsumoto K, Yoshida M, Shindo M. Angew. Chem., Int. Ed. 2016; 55: 5272
• 7e Fujimoto S, Matsumoto K, Iwata T, Shindo M. Tetrahedron Lett. 2017; 58: 973
• 7f Nabavizadeh SM, Hosseini FN, Park C, Wu G, Abu-Omar MM. Dalton Trans. 2020; 49: 2477
• 8 We confirmed that contamination amount of Pd in 9.1 mg of Na₂PtCl₆ was under detection limit. We also tested the reaction using 1.0 mol % of Pd(OAc)₂ as a catalyst in the presence of 10 mol % of Cu(OAc)₂ without using ligands: this resulted in 2.5% yield with 0.40 of sym/asym regioselectivity
• 9a Hirano M, Sano K, Kanazawa Y, Komine N, Maeno Z, Mitsudome T, Takaya H. ACS Catal. 2018; 8: 5827
• 9b Kanazawa Y, Mitsudome T, Takaya H, Hirano M. ACS Catal. 2020; 10: 5909
• 10a Maphoru MV, Heveling J, Pillai SK. ChemPlusChem 2014; 79: 99
• 10b Maphoru MV, Heveling J, Pillai SK. Eur. J. Org. Chem. 2016; 2016: 331
• 10c Maphoru MV, Pillai SK, Heveling J. J. Catal. 2017; 348: 47
• 10d Fujimoto S, Matsumoto K, Iwata T, Shindo M. Tetrahedron Lett. 2017; 58: 973
• 10e Zhang X.-W, Shen S.-C, Hidajat K, Kawi S, Yu LE, Simon Ng KY. Catal. Lett. 2004; 96: 87
• 10f Nabavizadeh SM, Hosseini FN, Park C, Wu G, Abu-Omar MM. Dalton Trans. 2020; 49: 2477
• 10g Wagner AM, Hickman AJ, Sanford MS. J. Am. Chem. Soc. 2013; 135: 15710
• 10h Chen M, Rago AJ, Dong G. Angew. Chem., Int. Ed. 2018; 57: 16205
• 11a Ishikawa S, Hamada T, Manabe K, Kobayashi S. Synthesis 2005; 13: 2176
• 11b Bednářová E, Malatinec S, Kotora M. Molecules 2020; 25: 958
• 12 A typical procedure for a batch reaction was described using Entry 3 of Table 4, for example: To an autoclave containing a magnetic stirring bar, dimethyl phthalate (6.1 mmol), Na₂PtCl₄ (0.061 mmol), Cu(OAc)₂ (0.61 mmol), and acetic acid (1.0 mL) were added, and the autoclave was heated at 190 °C to start the reaction. After 2 h, the reaction mixture was diluted with EtOAc and filtered through celite. The obtained solution was then concentrated and subjected to analysis by GC-FID
• 13 Typical procedure for a continuous-flow reaction: A thoroughly mixed composite of Pt/SiO₂ (0.4 g, Pt 0.25 mmol) and Celite was packed into a stainless steel column (Φ10 × 100 mm) equipped with a filter and a column head at one end. A double-inlet column head, capable of independently introducing gas and liquid into the reactor, was attached to the other end of the column. Dimethyl phthalate (110 mmol), copper(II) acetate monohydrate (1.6 mmol), and acetic acid (25 mL) were combined and stirred at 90 °C to form a homogeneous substrate solution, and the reservoir temperature was maintained at 90 °C using a plate heater. Toluene was initially fed into the reactor. Subsequently, dry air flow was initiated, and the reactor was heated to 200 °C. The feed was then switched from toluene to the substrate solution, and the outflow was connected to the reservoir to create a recirculation system. This recirculation system was driven for 16 h, and a sample of the solution was taken to be subject to analysis by GC-FID