Boronic Acids and Their Derivatives as Continuous-Flow-Friendly Alkyl Radical Precursors

Abstract

Since its recognition as an enabling tool to form challenging C–C and C–heteroatom bonds under mild and sustainable conditions, photoredox catalysis has been in the spotlight within the synthetic community. As a consequence, the interest in developing novel synthetic strategies has spiked together with the need to define suitable technologies to overcome scale-up issues dictated by the Bouguer–Beer–Lambert law. In this context, continuous-flow reactors play a major role in increasing the efficiency of a given photocatalyzed reaction, thus rendering scale-up processes more accessible. In the alkyl radical precursor landscape, boron-based species have begun to play a predominant role. Though the reactivity of trifluoroborates has been deeply investigated, the interest in using other boron species as radical precursors in photocatalyzed reactions has recently arisen. This late exploration lies in the fact that the high oxidation potential of boronic acids (BAs) hinders their possible applications. Nevertheless, to circumvent this issue, a diverse array of activation modes has been developed, exploiting in most cases the inherent Lewis acidity of the boronic acid. The aim of this Account is to highlight our recent contribution to this vibrant field with a focus on broad applicability, selectivity, and scalability via continuous-flow methodology. For the sake of clarity, the Account is discussed under the following sections.

1 Introduction

2 Why Photochemistry in Flow?

2.1 Preliminary Considerations

2.2 Batch vs. Flow Photochemical Reactions

2.3 Commercially Available Lab-Scale Solutions for Photoflow Chemistry

3 Organoboron Compounds

3.1 The Evolution of Organoboron Compounds as Radical Precursors in Photoredox Catalysis

3.2 Organoboron Compounds in Flow

4 Activation of Boronic Acids towards Radical Formation

4.1 Giese-Type Addition

4.2 Petasis Reaction

4.3 Light-Driven Four-Component Reaction

4.4 Minisci Reaction

5 Conclusion and Future Perspective

Key words

photoredox catalysis - continuous-flow chemistry - boronic acid - free radicals

Publikationsverlauf

Eingereicht: 17. Januar 2023

Angenommen nach Revision: 04. April 2023

Accepted Manuscript online:
04. April 2023

Artikel online veröffentlicht:
08. Mai 2023

• References

• 1a Walling C. Tetrahedron 1985; 41: 3887
• 1b Ingold KU. Pure Appl. Chem. 1997; 69: 241
• 2 Kolbe H. Ann. Chem. Pharm. 1848; 64: 339

For selected general reviews of radical chemistry, see:
• 3a Free Radicals: Dynamics of Elementary Processes, Vol. 1 . Kochi JK. Wiley-Interscience; New York: 1973
• 3b Curran DP. Synthesis 1988; 6: 417
• 3c Curran DP. Synthesis 1988; 7: 489
• 3d Jasperse CP, Curran DP, Fevig TL. Chem. Rev. 1991; 91: 1237
• 3e Radicals in Organic Synthesis . Renaud P, Sibi M. Wiley-VCH; Weinheim: 2001
• 3f Togo H. Advanced Free Radical Reactions for Organic Synthesis. Elsevier; Amsterdam: 2003
• 3g Zard SZ. Radical Reactions in Organic Synthesis . Oxford University Press; Oxford: 2003
• 4 Kuivila HG, Menapace LW. J. Org. Chem. 1963; 28: 2165
• 5 Baguley PA, Walton JC. Angew. Chem. Int. Ed. 1998; 37: 3072
• 6a Barton DH. R, Beaton JM, Geller LE, Pechet MM. J. Am. Chem. Soc. 1960; 82: 2640
• 6b Barton DH. R, Beaton JM. J. Am. Chem. Soc. 1960; 82: 2641
• 6c Barton DH. R, Beaton JM, Geller LE, Pechet MM. J. Am. Chem. Soc. 1961; 83: 4076

Also see:
• 6d Walling C, Padwa A. J. Am. Chem. Soc. 1961; 83: 2207
• 7 Prier CK, Rankic DA, MacMillan DW. C. Chem. Rev. 2013; 113: 5322
• 8 Kalyanasundaram K. Coord. Chem. Rev. 1982; 46: 159
• 9 Juris A, Balzani V, Barigelletti F, Campagna S, Belser P, von Zelewsky A. Coord. Chem. Rev. 1988; 84: 85

For selected reviews, see:
• 10a Shaw MH, Twilton J, MacMillan DW. C. J. Org. Chem. 2016; 81: 6898
• 10b Romero NA, Nicewicz DA. Chem. Rev. 2016; 116: 10075
• 11 Donnelly K, Baumann M. J. Flow Chem. 2021; 11: 223
• 12a Lu H, Schmidt MA, Jensen KF. Lab Chip 2001; 1: 22
• 12b Ueno K, Kitagawa F, Kitamura N. Lab Chip 2002; 2: 231
• 13a Feehs RH. US3554887A, 1971
• 13b Doede CM, Walker CA. Chem. Eng. 1955; 62: 159
• 14a Pistorius A, DeGrip W. In Encyclopedia of Spectroscopy and Spectrometry, 2^nd ed. . Lindon J, Tranter G, Koppenaal D. Academic Press; Amsterdam: 2010: 142-152
• 14b Rodger A, Sanders K. In Encyclopedia of Spectroscopy and Spectrometry, 2^nd ed. . Lindon J, Tranter G, Koppenaal D. Academic Press; Amsterdam: 2010: 166-173
• 14c Mayerhöfer T, Mutschke H, Popp J. ChemPhysChem 2016; 17: 1948
• 14d Mayerhöfer T, Popp J. ChemPhysChem 2019; 20: 511
• 15a Buglioni L, Raymenants F, Slattery A, Zondag SD. A, Noël T. Chem. Rev. 2022; 122: 2752
• 15b Cambié D, Bottecchia C, Straathof NJ. W, Hessel V, Noël T. Chem. Rev. 2016; 116: 10276
• 16 Dong Z, Wen Z, Zhao F, Kuhn S, Noël T. Chem. Eng. Sci.: X 2021; 10: 100097
• 17 Pitzer L, Schäfer F, Glorius F. Angew. Chem. Int. Ed. 2019; 58: 8572

Selected protocols:
• 18a Britton J, Jamison TF. Nat. Protoc. 2017; 12: 2423
• 18b Straathof NJ. W, Su Y, Hessel V, Noël T. Nat. Protoc. 2016; 11: 10
• 18c Hone CA, Kappe CO. Chem. Methods 2021; 1: 1
• 19 Sender M, Ziegenbalg S. Chem. Ing. Tech. 2017; 89: 1159
• 20 Chemistry of the Non-Metals . Steudel R. de Gruyter; Berlin: 1977
• 21a Marotta A, Adams CE, Molloy J. Angew. Chem. Int. Ed. 2022; 134: e202207067
• 21b Pillitteri S, Ranjan P, Van der Eycken EV, Sharma U. Adv. Synth. Catal. 2022; 364: 1643
• 21c Duret G, Quinlan R, Bisseret P, Blanchard N. Chem. Sci. 2015; 6: 5366
• 22 Tellis JC, Kelly CB, Primer DN, Jouffroy M, Patel NR, Molander GA. Acc. Chem. Res. 2016; 49: 1429
• 23 Williams JL. R, Doty JC, Grisdale PJ, Searle R, Regan TH, Happ GP, Maier DP. J. Am. Chem. Soc. 1967; 89: 5153
• 24 Yasu Y, Koike T, Akita M. Adv. Synth. Catal. 2012; 354: 3414
• 25a Tellis JC, Primer DN, Molander GA. Science 2014; 345: 433
• 25b Zuo Z, Ahneman DT, Chu L, Terrett JA, Doyle AG, MacMillan DW. Science 2014; 345: 437
• 25c Chan AY, Perry IB, Bissonnette NB, Buksh BF, Edwards GA, Frye LI, Garry OL, Lavagnino MN, Li BX, Liang Y, Mao E, Millet A, Oakley JV, Reed NL, Sakai HA, Seath CP, Macmillan DW. C. Chem. Rev. 2022; 122: 1485
• 26 Hartwig JF. Organotransition Metal Chemistry: From Bonding to Catalysis. University Science; Sausalito: 2010
• 27 Tasker SZ, Standley EA, Jamison TF. Nature 2014; 509: 299
• 28a Huang H, Jia K, Chen Y. Angew. Chem. Int. Ed. 2015; 54: 1881
• 28b Li G.-X, Morales-Rivera CA, Wang Y, Gao F, He G, Liu P, Chen G. Chem. Sci. 2016; 7: 6407
• 28c Li X, Han M.-Y, Wang B, Wang L, Wang M. Org. Biomol. Chem. 2019; 17: 6612
• 29 Lima F, Kabeshov MA, Tran DN, Battilocchio C, Sedelmeier J, Sedelmeier G, Schenkel B, Ley SV. Angew. Chem. Int. Ed. 2016; 55: 14085
• 30 Lima F, Sharma UK, Grunenberg L, Saha D, Johannsen S, Sedelmeier J, Van der Eycken EV, Ley SV. Angew. Chem. Int. Ed. 2017; 56: 15136

For activation with external oxidants, see:
• 31a Huang H, Zhang G, Gong L, Zhang S, Chen Y. J. Am. Chem. Soc. 2014; 136: 2280
• 31b Li G.-X, Morales-Rivera CA, Wang Y, Gao F, He G, Liu P, Chen G. Chem. Sci. 2016; 7: 6407
• 31c Zhang L, Liu Z.-Q. Org. Lett. 2017; 19: 6594
• 31d Dong J, Yue F, Song H, Liu Y, Wang Q. Chem. Commun. 2020; 56: 12652

For activation with bases, see:
• 31e Iwata Y, Tanaka Y, Kubosaki S, Morita T, Yoshimi Y. Chem. Commun. 2018; 54: 1257
• 31f Shi D, Xia C, Liu C. CCS Chem. 2021; 3: 1718

For activation with ArLi, see:
• 31g Shu C, Noble A, Aggarwal VK. Angew. Chem. Int. Ed. 2019; 58: 3870
• 31h Clausen F, Kischkewitz M, Bergander K, Studer A. Chem. Sci. 2019; 10: 6210

For solvent-assisted activation approaches, see:
• 31i Chilamari M, Immel JR, Bloom S. ACS Catal. 2020; 10: 12727
• 31j Ranjan P, Pillitteri S, Coppola G, Oliva M, Van der Eycken EV, Sharma UK. ACS Catal. 2021; 11: 10862
• 31k Oliva M, Ranjan P, Pillitteri S, Coppola GA, Messina M, Van der Eycken EV, Sharma UK. iScience 2021; 24: 103134

For dual role of the substrate as Bas activator and reagent, see:
• 31l Yue F, Dong J, Liu Y, Wang Q. Org. Lett. 2021; 23: 2477
• 31m Gockel N, Lee S, Gay BL, Hull KL. ACS Catal. 2021; 11: 5166
• 31n Pillitteri S, Ranjan P, Ojeda-Carralero GM, Vázquez-Amaya LY, Alfonso-Ramos JE, Van der Eycken EV, Sharma UK. Org. Chem. Front. 2022; 9: 6958
• 32 Speckmeier E, Maier TC. J. Am. Chem. Soc. 2022; 144: 9997
• 33 Lovering F, Bikker J, Humblet C. J. Med. Chem. 2009; 52: 6752
• 34 Han F.-S. Chem. Soc. Rev. 2013; 42: 5270
• 35 DeLano TJ, Bandarage UK, Palaychuk N, Green J, Boyd MJ. J. Org. Chem. 2016; 81: 12525
• 36 Cauley AN, Sezen-Edmonds M, Simmons EM, Cavallaro CL. React. Chem. Eng. 2021; 6: 1666
• 37 Lima F, Grunenberg L, Rahman HB, Labes R, Sedelmeier J, Ley SV. Chem. Commun. 2018; 54: 5606
• 38a de Graaff C, Ruijter E, Orru RV. Chem. Soc. Rev. 2012; 41: 3969
• 38b Cioc RC, Ruijter E, Orru RV. Green Chem. 2014; 16: 2958
• 38c Abdelraheem EM, Shaabani S, Dömling A. Drug Discov. Today Technol. 2018; 29: 11
• 39 Petasis NA, Akritopoulou I. Tetrahedron Lett. 1993; 34: 583
• 40 Wu P, Givskov M, Nielsen TE. Chem. Rev. 2019; 119: 11245
• 41 Yi J, Badir SO, Alam R, Molander GA. Org. Lett. 2019; 21: 4853
• 42 Oliva M, Martens F, Van der Eycken EV, Sharma UK. STAR Protoc. 2022;  3: 101162
• 43 Vázquez-Amaya L, Dootselaere B, Ojeda-Carralero GM, Pillitteri S, Van der Eycken EV, Sharma UK. ChemRxiv 2023; preprint DOI: 10.26434/chemrxiv-2023-v2c44.
• 44 Minisci F, Bernardi R, Bertini F, Galli R, Perchinummo M. Tetrahedron 1971; 27: 3575
• 45 Proctor RS, Phipps RJ. Angew. Chem. Int. Ed. 2019; 58: 13666
• 46a Beatty JW, Douglas JJ, Cole KP, Stephenson CR. J. Nat. Commun. 2015; 6: 7919
• 46b Mousseau JJ, Perry MA, Bundesmann MW, Chinigo GM, Choi C, Gallego G, Hicklin RW, Hoy S, Limburg DC, Sach NW, Zhang Y. ACS Catal. 2022; 12: 600
• 46c Graham MA, Noonan G, Cherryman JH, Douglas JJ, Gonzalez M, Jackson LV, Leslie K, Liu Z, McKinney D, Munday RH, Parsons CD, Whittaker DT. E, Zhang E, Zhang J. Org. Process Res. Dev. 2021; 25: 57