Addition of a Phosphinoboronate Ester to Borole and Borafluorene

Dedicated to Professor Donald Matteson and in memory of the late Professor Stephen Westcott in recognition of their contributions to organoboron chemistry.

Abstract

The additions of the phosphinoboronate ester Ph₂PBpin to an antiaromatic borole and a borafluorene is reported. The Lewis acid/base adducts are obtained in excellent yields and represent the first P-donor adducts of Ph₂PBpin.

Key words

pinacol diphenylphosphinoboronate - boroles - borafluorenes - antiaromaticity - Lewis acid

Publication History

Received: 27 July 2023

Accepted after revision: 22 August 2023

Accepted Manuscript online:
23 August 2023

Article published online:
22 September 2023

• References and Notes

• 1 Paine RT, Noeth H. Chem. Rev. 1995; 95: 343
• 2 Gaumont AC, Carboni B. In Science of Synthesis, Vol. 6, Chap. 6.1.16. Kaufmann DE. Thieme; Stuttgart: 2005: 485
• 3 Bailey JA, Pringle PG. Coord. Chem. Rev. 2015; 297: 77
• 4 Power PP. Angew. Chem., Int. Ed. Engl. 1990; 29: 449
• 5 Geier SJ, Gilbert TM, Stephan DW. J. Am. Chem. Soc. 2008; 130: 12632
• 6 Ordyszewska A, Szynkiewicz N, Chojnacki J, Grubba R. Inorg. Chem. 2022; 61: 4361
• 7 Geier SJ, Gilbert TM, Stephan DW. Inorg. Chem. 2011; 50: 336
• 8 Daley EN, Vogels CM, Geier SJ, Decken A, Doherty S, Westcott SA. Angew. Chem. Int. Ed. 2015; 54: 2121
• 9 Breunig JM, Hübner A, Bolte M, Wagner M, Lerner H.-W. Organometallics 2013; 32: 6792
• 10 Geier SJ, Vogels CM, Mellonie NR, Daley EN, Decken A, Doherty S, Westcott SA. Chem. Eur. J. 2017; 23: 14485
• 11 Zhu D, Qu Z.-W, Stephan DW. Dalton Trans. 2020; 49: 901
• 12 Geier SJ, LaFortune JH. W, Zhu D, Kosnik SC, Macdonald CL. B, Stephan DW, Westcott SA. Dalton Trans. 2017; 46: 10876
• 13 Trofimova A, LaFortune JH. W, Qu Z.-W, Westcott SA, Stephan DW. Chem. Commun. 2019; 55: 12100
• 14 LaFortune JH. W, Trofimova A, Cummings H, Westcott SA, Stephan DW. Chem. Eur. J. 2019; 25: 12521
• 15 Szynkiewicz N, Ordyszewska A, Chojnacki J, Grubba R. RSC Adv. 2019; 9: 27749
• 16 Szynkiewicz N, Chojnacki J, Grubba R. Inorg. Chem. 2020; 59: 6332
• 17 Murphy MC, Trofimova A, LaFortune JH. W, Vogels CM, Geier SJ, Binder JF, Macdonald CL. B, Stephan DW, Westcott SA. Dalton Trans. 2020; 49: 5092
• 18 Szynkiewicz N, Ordyszewska A, Chojnacki J, Grubba R. Inorg. Chem. 2021; 60: 3794
• 19 Dou D, Westerhausen M, Wood GL, Duesler EN, Paine RT, Linti G, Nöth H. Chem. Ber. 1993; 126: 379
• 20 Linti G, Nöth H, Paine RT. Chem. Ber. 1993; 126: 875
• 21 Chen T, Jackson J, Jasper SA, Duesler EN, Nöth H, Paine RT. J. Organomet. Chem. 1999; 582: 25
• 22 Vogel U, Hoemensch P, Schwan K.-C, Timoshkin AY, Scheer M. Chem. Eur. J. 2003; 9: 515
• 23 Vogel U, Schwan K.-C, Hoemensch P, Scheer M. Eur. J. Inorg. Chem. 2005; 2005: 1453
• 24 Vogel U, Timoshkin AY, Schwan K.-C, Bodensteiner M, Scheer M. J. Organomet. Chem. 2006; 691: 4556
• 25 Schwan K.-C, Timoskin AY, Zabel M, Scheer M. Chem. Eur. J. 2006; 12: 4900
• 26 Adolf A, Zabel M, Scheer M. Eur. J. Inorg. Chem. 2007; 2007: 2136
• 27 Adolf A, Vogel U, Zabel M, Timoshkin AY, Scheer M. Eur. J. Inorg. Chem. 2008; 2008: 3482
• 28 Schwan K.-C, Adolf A, Thoms C, Zabel M, Timoshkin AY, Scheer M. Dalton Trans. 2008; 5054
• 29 Schwan K.-C, Vogel U, Adolf A, Zabel M, Scheer M. J. Organomet. Chem. 2009; 694: 1189
• 30 Tian R, Mathey F. Chem. Eur. J. 2012; 18: 11210
• 31 Amgoune A, Ladeira S, Miqueu K, Bourissou D. J. Am. Chem. Soc. 2012; 134: 6560
• 32 Kubo K, Kawanaka T, Tomioka M, Mizuta T. Organometallics 2012; 31: 2026
• 33 Morris LJ, Rajabi NA, Hill MS, Manners I, McMullin CL, Mahon MF. Dalton Trans. 2020; 49: 14584
• 34 Moussa ME, Marquardt C, Hegen O, Seidl M, Scheer M. New J. Chem. 2021; 45: 14916
• 35 Moussa ME, Kahoun T, Marquardt C, Ackermann MT, Hegen O, Seidl M, Timoshkin AY, Virovets AV, Bodensteiner M, Scheer M. Chem. Eur. J. 2023; 29: e202203206
• 36 Lehnfeld F, Hegen O, Balázs G, Timoshkin AY, Scheer M. Z. Anorg. Allg. Chem. 2023; 649: e202200265
• 37 Ordyszewska A, Chojnacki J, Grubba R. Dalton Trans. 2023; 52: 4161
• 38 Fritzemeier RG, Nekvinda J, Vogels CM, Rosenblum CA, Slebodnick C, Westcott SA, Santos WL. Angew. Chem. Int. Ed. 2020; 59: 14358
• 39 Braunschweig H, Kupfer T. Chem. Commun. 2011; 47: 10903
• 40 Barnard JH, Yruegas S, Huang K, Martin CD. Chem. Commun. 2016; 52: 9985
• 41 Su X, Bartholome TA, Tidwell JR, Pujol A, Yruegas S, Martinez JJ, Martin CD. Chem. Rev. 2021; 121: 4147
• 42 Nguyen MT, van Trang N, Dung TN, Nguyen HM. T. In Comprehensive Heterocyclic Chemistry IV, Vol. 3, Chap. 3.18. Black DS, Cossy J, Stevens CV. Elsevier; Oxford: 2022: 833
• 43 CCDC 2279046 and 2279047 contain the supplementary crystallographic data for compounds 1 and 2. The data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/structures
• 44 Berger CJ, He G, Merten C, McDonald R, Ferguson MJ, Rivard E. Inorg. Chem. 2014; 53: 1475
• 45 Braunschweig H, Chiu C.-W, Damme A, Ferkinghoff K, Kraft K, Radacki K, Wahler J. Organometallics 2011; 30: 3210
• 46 Yruegas S, Huang K, Wilson DJ. D, Dutton JL, Martin CD. Dalton Trans. 2016; 45: 9902
• 47 Caputo BC, Manning ZJ, Barnard JH, Martin CD. Polyhedron 2016; 114: 273
• 48 Biswas S, Oppel IM, Bettinger HF. Inorg. Chem. 2010; 49: 4499
• 49 Müller M, Maichle-Mössmer C, Bettinger HF. Angew. Chem. Int. Ed. 2014; 53: 9380
• 50 Zhang Z, Edkins RM, Haehnel M, Wehner M, Eichhorn A, Mailänder L, Meier M, Brand J, Brede F, Müller-Buschbaum K, Braunschweig H, Marder TB. Chem. Sci. 2015; 6: 5922
• 51 Yruegas S, Wilson C, Dutton JL, Martin CD. Organometallics 2017; 36: 2581
• 52 Laperriere LE, Yruegas S, Martin CD. Tetrahedron 2019; 75: 937
• 53 Adducts 1 and 2: General Procedure A solution of PPh₂Bpin (0.50 mmol, 156 mg) in benzene (4 mL) was added dropwise to a solution of pentaphenyl-1H-borole or 9-phenyl-9-borafluorene (0.5 mmol) in benzene (4 mL) at rt. The solution instantly became colorless, and the mixture was stirred for 10 min at rt. The solvent was then removed in vacuo and the residue was washed with cold pentane (2 × 5 mL) and dried in vacuo. 1 Pale-yellow powder; yield: 319 mg (84%,); mp 216–219 °C. FTIR (neat): (ranked intensity) 1593 (11), 1483 (8), 1438 (9), 1340 (12), 1245 (5), 1129 (2), 1028 (13), 958 (14), 841 (4), 792 (6), 741 (7), 693 (1), 542 (10), 505 (3), 460 (15) cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 7.77 (d, J = 6.9 Hz, 2 H), 7.43–7.38 (m, 6 H), 7.33–7.27 (m, 3 H), 7.24–7.22 (m, 4 H), 6.90–6.85 (m, 6 H), 6.82–6.78 (m, 6 H), 6.75–6.74 (m, 4 H), 6.59 (d, J = 7.0 Hz, 4 H), 1.01 (s, 12 H). ¹³C{¹H} NMR (101 MHz, CDCl₃): δ = 154.5, 153.5, 153.4, 143.5, 140.5, 135.4 (d, J = 8.5 Hz), 135.2 (d, J = 12.8 Hz), 130.4 (d, J = 2.6 Hz), 130.3 (d, J = 2.6 Hz), 129.7, 127.7, 127.6, 127.3, 126.9, 126.8, 125.9, 125.4, 125.2, 125.0, 124.3, 86.5, 86.5, 24.6. ³¹P NMR (162 MHz, CDCl₃): δ = –34.2. ¹¹B NMR (128 MHz, CDCl₃): δ = 30.8, –5.2. HRMS (ESI): the adduct peak was not observed in the HRMS. Anal. Calcd for C₅₂H₄₇B₂O₂P: C, 82.56; H, 6.26. Found: C 82.36, H 6.32. Single crystals of 1 for X-ray diffraction studies were grown from a CH₂Cl₂ solution by vapor diffusion into toluene. 2 White powder; yield: 256 mg (93%,); mp 189–191 °C. FTIR (neat): (ranked intensity) 1483 (14), 1435 (8), 1373 (12), 1348 (10), 1244 (6), 1128 (4), 1103 (13), 961 (11), 836 (5), 734 (1), 696 (3), 647 (9), 616 (15), 506 (2), 427 (7) cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 7.65 (d, J = 7.7 Hz, 4 H), 7.55 (d, J = 7.2 Hz, 2 H), 7.41 (td, J = 7.2, 1.6 Hz, 2 H), 7.30–7.15 (m, 13 H), 7.12 (t, J = 7.2 Hz, 2 H), 1.15 (s, 12 H). ¹³C{¹H} NMR (101 MHz, CDCl₃): δ = 153.0, 149.4, 134.6 (d, J = 7.5 Hz), 134.2, 132.9, 130.5 (d, J = 2.6 Hz), 128.3 (d, J = 9.5 Hz), 127.5, 126.5, 126.2, 125.8, 125.6, 125.6, 86.6, 86.6, 24.7. ³¹P NMR (162 MHz, CDCl₃): δ = –35.2. ¹¹B NMR (128 MHz, CDCl₃): δ = 30.9, –9.3. HRMS (ESI): m/z [M + H] calcd for C₃₆H₃₆B₂O₂P: 553.2634; found: 553.2610. Anal. Calcd for C₃₆H₃₅B₂O₂P: C, 78.29; H, 6.39. Found: C, 78.54; H, 6.55. Single crystals for X-ray diffraction studies were grown from a CH₂Cl₂ solution of 2 by vapor diffusion into toluene.