Recent Advances in Copper-Catalyzed Asymmetric Hydroboration of Electron-Deficient Alkenes: Methodologies and Mechanism

Jing-Biao Chen; Andrew Whiting

doi:10.1055/s-0037-1609583

Synthesis, Table of Contents

Synthesis 2018; 50(19): 3843-3861
DOI: 10.1055/s-0037-1609583

short review

Recent Advances in Copper-Catalyzed Asymmetric Hydroboration of Electron-Deficient Alkenes: Methodologies and Mechanism

Jing-Biao Chen

Centre for Sustainable Chemical Processes, Department of Chemistry, Durham University, Science Laboratories, South Road, Durham DH1 3LE, UK Email: andy.whiting@durham.ac.uk

,

Andrew Whiting *

Centre for Sustainable Chemical Processes, Department of Chemistry, Durham University, Science Laboratories, South Road, Durham DH1 3LE, UK Email: andy.whiting@durham.ac.uk

› Author Affiliations

Abstract

All articles of this category

Abstract

The efficient synthesis of enantioenriched organoboron compounds has been recognized as an important topic in recent years. As an update review, this article aims to select key achievements in copper-catalyzed, electron-deficient alkene enantioselective hydroboration methodologies since the beginning of 2017. In addition, it covers relevant mechanistic investigations developed over the last six years, as well as total synthesis applications for preparing 1,3-diols as important medicinal intermediates.

1 Introduction

2 Methodologies for Copper-Catalyzed Hydroboration

2.1 α,β-Unsaturated Ketones and Imines

2.2 α,β-Unsaturated Esters and Cyanides

2.3 Aryl Alkenes and Alkyl Alkenes

3 Mechanistic Investigations on the Copper-Catalyzed Hydroboration

3.1 A Cu–BX₂ Intermediate

3.1.1 Experimental Analysis

3.1.2 Borylative Difunctionalization Methodologies

3.1.3 Density Functional Theory

3.2 A Cu–H Intermediate

3.3 Other Mechanistic Proposals

4 Synthetic Applications: Chiral 1,3-Diols

5 Conclusions and Outlook

Key words

alkenes - copper catalysis - hydroboration - asymmetric - mechanism - 1,3-diols - total synthesis

Full Text

References

References

1a Brown HC. Ramachandran PV. Pure Appl. Chem. 1994; 66: 201
1b Matteson DS. J. Organomet. Chem. 1999; 581: 51
1c Boronic Acids . Hall DG. Wiley-VCH; Weinheim: 2011
1d Suzuki A. Angew. Chem. Int. Ed. 2011; 50: 6723
1e Kaur P. Khatik GL. Nayak SK. Curr. Org. Synth. 2017; 14: 665

For applications in pharmaceuticals and bioactive molecules, see:

2a Woodward RB. Au-Yeung BW. Balaram P. Browne LJ. Ward DE. Card PJ. Chen CH. J. Am. Chem. Soc. 1981; 103: 3213
2b Flores-Parra A. Contreras R. Coord. Chem. Rev. 2000; 196: 85
2c Yang W. Gao X. Wang B. Med. Res. Rev. 2003; 23: 346
2d Tobert JA. Nat. Rev. Drug Discovery 2003; 3: 178
2e Petasis NA. Aust. J. Chem. 2007; 60: 795
2f Kumar RN. Meshram HM. Tetrahedron Lett. 2011; 52: 1003
2g Smoum R. Rubinstein A. Dembitsky VM. Srebnik M. Chem. Rev. 2012; 112: 4156

For selected reviews on borylation and its transformations, see:

3a Ishiyama T. Miyaura N. J. Organomet. Chem. 2000; 611: 392
3b Crudden CM. Glasspoole BW. Lata CJ. Chem. Commun. 2009; 6704
3c Hall DG. Lee JC. H. Ding J. Pure Appl. Chem. 2012; 84: 2263
3d Lennox AJ. J. Lloyd-Jones GC. Chem. Soc. Rev. 2014; 43: 412
3e Leonori D. Aggarwal VK. Acc. Chem. Res. 2014; 47: 3174
3f Xu L. Zhang S. Li P. Chem. Soc. Rev. 2015; 44: 8848
3g Leonori D. Aggarwal VK. Angew. Chem. Int. Ed. 2015; 54: 1082
3h Lee A.-L. Org. Biomol. Chem. 2016; 14: 5357
3i Chatterjee N. Goswami A. Adv. Synth. Catal. 2017; 359: 358
3j Scharnagl FK. Bose SK. Marder TB. Org. Biomol. Chem. 2017; 15: 1738
3k Yang J.-M. Li Z.-Q. Zhu S.-F. Chin. J. Org. Chem. 2017; 37: 2481
3l Armstrong RJ. Aggarwal VK. Synthesis 2017; 49: 3323
3m Willemse T. Schepens W. van Vlijmen HW. T. Maes BU. W. Ballet S. Catalysts 2017; 7: 74
3n Nallagonda R. Padala K. Masarwa A. Org. Biomol. Chem. 2018; 16: 1050

4a Dang L. Lin Z. Marder TB. Chem. Commun. 2009; 3987
4b Calow AD. J. Whiting A. Org. Biomol. Chem. 2012; 10: 5485

For selected reviews relevant to the topic of borylation, see:

5a Ishiyama T. Miyaura N. Chem. Rec. 2004; 3: 271
5b Miyaura N. Bull. Chem. Soc. Jpn. 2008; 81: 1535
5c Cid J. Gulyás H. Carbό JJ. Fernández E. Chem. Soc. Rev. 2012; 41: 3558
5d Yun J. Asian J. Org. Chem. 2013; 2: 1016
5e Westcott SA. Fernández E. Adv. Heterocycl. Chem. 2015; 63: 39
5f Hensel A. Oestreich M. Top. Organomet. Chem. 2015; 58: 135
5g Tsuji Y. Fujihara T. Chem. Rec. 2016; 16: 2294
5h Yoshida H. Chem. Rec. 2016; 16: 419
5i Neeve EC. Geier SJ. Mkhalid IA. I. Westcott SA. Marder TB. Chem. Rev. 2016; 116: 9091
5j Collins BS. L. Wilson CM. Myers EL. Aggarwal VK. Angew. Chem. Int. Ed. 2017; 56: 11700
5k Lawson JR. Melen RL. Inorg. Chem. 2017; 56: 8627
5l Lawson JR. Melen RL. Organomet. Chem. 2017; 41: 1
5m Fujihara T. Tsuji Y. Synthesis 2018; 50: 1737
5n Verma PK. Shegavi ML. Bose SK. Geetharani K. Org. Biomol. Chem. 2018; 16: 857
5o Yan G. Huang D. Wu X. Adv. Synth. Catal. 2018; 360: 1040

For selected reviews on diboration, see:

6a Marder TB. Norman NC. Top. Catal. 1998; 5: 63
6b Dembitsky VM. Ali HA. Srebnik M. Appl. Organomet. Chem. 2003; 17: 327
6c Beletskaya I. Moberg C. Chem. Rev. 2006; 106: 2320
6d Bonet A. Sole C. Gulyás H. Fernández E. Org. Biomol. Chem. 2012; 10: 6621
6e Zhao F. Jia X. Li P. Zhao J. Zhou Y. Wang J. Liu H. Org. Chem. Front. 2017; 4: 2235

For selected reviews on borylative bifunctionalization, see:

7a Suginome M. Ito Y. J. Organomet. Chem. 2003; 680: 43
7b Oestreich M. Hartmann E. Mewald M. Chem. Rev. 2013; 113: 402
7c Buñuel E. Cárdenas DJ. Eur. J. Org. Chem. 2016; 5446
7d Cuenca AB. Shishido R. Ito H. Fernández E. Chem. Soc. Rev. 2017; 46: 415

For selected reviews on C–H borylation, see:

8a Ishiyama T. Miyaura N. J. Organomet. Chem. 2003; 680: 3
8b Ishiyama T. Miyaura N. Pure Appl. Chem. 2006; 78: 1369
8c Mkhalid IA. I. Barnard JH. Marder TB. Murphy JM. Hartwig JF. Chem. Rev. 2010; 110: 890
8d Hartwig JF. Chem. Soc. Rev. 2011; 40: 1992
8e Hartwig JF. Acc. Chem. Res. 2012; 45: 864
8f Ros A. Fernández R. Lassaletta JM. Chem. Soc. Rev. 2014; 43: 3229
8g Shinokubo H. Proc. Jpn. Acad., Ser. B 2014; 90: 1
8h Geier SJ. Westcott SA. Rev. Inorg. Chem. 2015; 35: 69
8i Xu L. Wang G. Zhang S. Wang H. Wang L. Liu L. Jiao J. Li P. Tetrahedron 2017; 73: 7123

For selected reviews on C–X borylation, see:

9a Murata M. Heterocycles 2012; 85: 1795
9b Chow WK. Yuen OY. Choy PY. So CM. Lau CP. Wong WT. Kwong FY. RSC Adv. 2013; 3: 12518
9c Kubota K. Iwamoto H. Ito H. Org. Biomol. Chem. 2017; 15: 285

For selected literature on Brown hydroboration, see:

10a Brown HC. Zweifel G. J. Am. Chem. Soc. 1961; 83: 486
10b Brown HC. Singaram B. Acc. Chem. Res. 1988; 21: 287
10c Beletskaya I. Pelter A. Tetrahedron 1997; 53: 4957
10d Crudden CM. Edwards D. Eur. J. Org. Chem. 2003; 4695
10e Carroll A.-M. O’Sullivan TP. Guiry PJ. Adv. Synth. Catal. 2005; 347: 609
10f Vogels CM. Westcott SA. Curr. Org. Chem. 2005; 9: 687
10g Huang S. Xie Y. Wu S. Jia M. Wang J. Xu W. Fang H. Curr. Org. Synth. 2013; 10: 683
10h Fujihara T. Semba K. Terao J. Tsuji Y. Catal. Sci. Technol. 2014; 4: 1699
10i Semba K. Fujihara T. Terao J. Tsuji Y. Tetrahedron 2015; 71: 2183
10j Liu Q. Tian B. Tian P. Tong X. Lin G.-Q. Chin. J. Org. Chem. 2015; 35: 1
10k Ito H. Pure Appl. Chem. 2018; 90: 703

For selected reviews on alkene hydroboration, see:

11a Lillo V. Bonet A. Fernández E. Dalton Trans. 2009; 2899
11b Thomas SP. Aggarwal VK. Angew. Chem. Int. Ed. 2009; 48: 1896
11c Stavber G. Časar Z. ChemCatChem 2014; 6: 2162
11d Liu Y. Zhang W. Chin. J. Org. Chem. 2016; 36: 2249
11e Chen J. Lu Z. Org. Chem. Front. 2018; 5: 260

For selected reviews on 1,3-diol synthesis and relevant strategies, see:

12a Masamune S. Choy W. Petersen JS. Sita LR. Angew. Chem., Int. Ed. Engl. 1985; 24: 1
12b Rychnovsky SD. Rogers BN. Richardson TI. Acc. Chem. Res. 1998; 31: 9
12c Bartoli G. Bartolacci M. Giuliani A. Marcantoni E. Massaccesi M. Eur. J. Org. Chem. 2005; 2867
12d Bode SE. Wolberg M. Müller M. Synthesis 2006; 557
12e Bonet A. Sole C. Gulyás H. Fernández E. Curr. Org. Chem. 2010; 14: 2531
12f Paterson I. Dalby SM. Maltas P. Isr. J. Chem. 2011; 51: 406
12g Alfaro R. Parra A. Alemán J. Tortosa M. Synlett 2013; 24: 804
12h Barreiro EM. Adrio LA. Hii KK. Brazier JB. Eur. J. Org. Chem. 2013; 1027
12i Joannou MV. Moyer BS. Meek SJ. J. Am. Chem. Soc. 2015; 137: 6176

13a Ibrahem I. Breistein P. Cόrdova A. Angew. Chem. Int. Ed. 2011; 50: 12036
13b Solé C. Tatla A. Mata JA. Whiting A. Gulyás H. Fernández E. Chem. Eur. J. 2011; 17: 14248
13c Solé C. Whiting A. Gulyás H. Fernández E. Adv. Synth. Catal. 2011; 353: 376
13d Ibrahem I. Breistein P. Cόrdova A. Angew. Chem. Int. Ed. 2011; 50: 12036
13e Calow AD. J. Batsanov AS. Fernández E. Solé C. Whiting A. Chem. Commun. 2012; 48: 11401
13f Kitanosono T. Xu P. Kobayashi S. Chem. Commun. 2013; 49: 8184
13g Calow AD. J. Batsanov AS. Pujol A. Solé C. Fernández E. Whiting A. Org. Lett. 2013; 15: 4810
13h Calow AD. J. Fernández E. Whiting A. Org. Biomol. Chem. 2014; 12: 6121
13i Kitanosono T. Xu P. Isshiki S. Zhu L. Kobayashi S. Chem. Commun. 2014; 50: 9336
13j He Z.-T. Zhao Y.-S. Tian P. Wang C.-C. Dong H.-Q. Lin G.-Q. Org. Lett. 2014; 16: 1426
13k Pujol A. Calow AD. J. Batsanov AS. Whiting A. Org. Biomol. Chem. 2015; 13: 5122
13l Pujol A. Whiting A. J. Org. Chem. 2017; 82: 7265

14 Jiang Q. Guo T. Yu Z. J. Org. Chem. 2017; 82: 1951
15 Wen L. Yue Z. Zhang H. Chong Q. Meng F. Org. Lett. 2017; 19: 6610
16 Tarrieu R. Dumas A. Thongpaen J. Vives T. Roisnel T. Dorcet V. Crévisy C. Baslé O. Mauduit M. J. Org. Chem. 2017; 82: 1880
17 Yasue R. Miyauchi M. Yoshida K. Adv. Synth. Catal. 2017; 359: 255
18 Chen L. Zou X. Zhao H. Xu S. Org. Lett. 2017; 19: 3676
19 Jana A. Trzybiński D. Woźniak K. Grela K. Chem. Eur. J. 2018; 24: 891
20 Green JC. Joannou MV. Murray SA. Zanghi JM. Meek SJ. ACS Catal. 2017; 7: 4441

21a Kong D. Han S. Wang R. Li M. Zi G. Hou G. Chem. Sci. 2017; 8: 4558
21b Kong D. Han S. Zi G. Hou G. Zhang J. J. Org. Chem. 2018; 83: 1924

22 Zhang Y. Wang M. Cao P. Liao J. Acta Chim. Sinica 2017; 75: 794

23a Lee Y. Hoveyda AH. J. Am. Chem. Soc. 2009; 131: 3160
23b Jia T. Cao P. Wang B. Lou Y. Yin X. Wang M. Liao J. J. Am. Chem. Soc. 2015; 137: 13760
23c Lee J. Radomkit S. Torker S. del Pozo J. Hoveyda AH. Nat. Chem. 2017; 10: 99
23d Huang C. Liu B. Chem. Commun. 2010; 46: 5280
23e Bai W.-J. Green JC. Pettus TR. R. J. Org. Chem. 2012; 77: 379

24 Chen B. Cao P. Liao Y. Wang M. Liao J. Org. Lett. 2018; 20: 1346

25a Corberán R. Mszar NW. Hoveyda AH. Angew. Chem. Int. Ed. 2011; 50: 7079
25b Wang Z. He X. Zhang R. Zhang G. Xu G. Zhang Q. Xiong T. Zhang Q. Org. Lett. 2017; 19: 3067
25c Wen L. Cheng F. Li H. Zhang S. Hong X. Meng F. Asian J. Org. Chem. 2018; 7: 103

26 Cai Y. Yang X.-T. Zhang S.-Q. Li F. Li Y.-Q. Ruan L.-X. Hong X. Shi S.-L. Angew. Chem. Int. Ed. 2018; 57: 1376
27 Kato K. Hirano K. Miura M. Chem. Eur. J. 2018; 24: 5775
28 Jang WJ. Song SM. Moon JH. Lee JY. Yun J. J. Am. Chem. Soc. 2017; 139: 13660

For selected examples on alkoxide or hydroxide base anion catalyzed alkene hydroboration, see:

29a Thorpe SB. Calderone JA. Santos WL. Org. Lett. 2012; 14: 1918
29b Sanz X. Lee GM. Pubill-Ulldemolins C. Bonet A. Gulyás H. Westcott SA. Bo C. Fernández E. Org. Biomol. Chem. 2013; 11: 7004
29c Cid J. Carbό JJ. Fernández E. Chem. Eur. J. 2014; 20: 3616
29d La Cascia E. Sanz X. Bo C. Whiting A. Fernández E. Org. Biomol. Chem. 2015; 13: 1328
29e Yang K. Song Q. Green Chem. 2016; 18: 932
29f Wu Y. Shan C. Ying J. Su J. Zhu J. Liu LL. Zhao Y. Green Chem. 2017; 19: 4169
29g Yamamoto E. Shishido R. Seki T. Ito H. Organometallics 2017; 36: 3019
29h Deng CM. Ma YF. Wen YM. ChemistrySelect 2018; 3: 1202
29i Huang X. Hu J. Wu M. Wang J. Peng Y. Song G. Green Chem. 2018; 20: 255
29j Yan L. Meng Y. Haeffner F. Leon RM. Crockett MP. Morken JP. J. Am. Chem. Soc. 2018; 140: 3663

For selected examples of methodologies proposing ‘Cu–BX₂’ as borylation intermediates, see:

30a Sasaki Y. Zhong C. Sawamura M. Ito H. J. Am. Chem. Soc. 2010; 132: 1226
30b Zhao L. Ma Y. Duan W. He F. Chen J. Song C. Org. Lett. 2012; 14: 5780
30c Kitanosono T. Kobayashi S. Asian J. Org. Chem. 2013; 2: 961
30d Tian B. Liu Q. Tong X. Tian P. Lin G.-Q. Org. Chem. Front. 2014; 1: 1116
30e Lee H. Lee BY. Yun J. Org. Lett. 2015; 17: 764
30f Wen Y. Xie J. Deng C. Li C. J. Org. Chem. 2015; 80: 4142
30g Iwamoto H. Kubota K. Ito H. Chem. Commun. 2016; 52: 5916
30h Kerchner HA. Montgomery J. Org. Lett. 2016; 18: 5760
30i Mazzacano TJ. Leon NJ. Waldhart GW. Mankad NP. Dalton Trans. 2017; 46: 5518
30j Kuang Z. Li B. Song Q. Chem. Commun. 2018; 54: 34

31a Semba K. Shinomiya M. Fujihara T. Terao J. Tsuji Y. Chem. Eur. J. 2013; 19: 7125
31b Kitanosono T. Xu P. Kobayashi S. Chem. Asian J. 2014; 9: 179

32 Calow AD. J. Solé C. Whiting A. Fernández E. ChemCatChem 2013; 5: 2233

For selected recent works on copper-catalyzed borylative difunctionalization, see:

33a Kubota K. Yamamoto E. Ito H. J. Am. Chem. Soc. 2013; 135: 2635
33b Itoh T. Matsueda T. Shimizu Y. Kanai M. Chem. Eur. J. 2015; 21: 15955
33c Hornillos V. Vila C. Otten E. Feringa BL. Angew. Chem. Int. Ed. 2015; 54: 7867
33d Jia T. Cao P. Wang D. Lou Y. Liao J. Chem. Eur. J. 2015; 21: 4918
33e Yang Y. Angew. Chem. 2016; 128: 353
33f Boreux A. Indukuri K. Gagosz F. Riant O. ACS Catal. 2017; 7: 8200
33g Fujihara T. Sawada A. Yamaguchi T. Tani Y. Terao J. Tsuji Y. Angew. Chem. Int. Ed. 2017; 56: 1539
33h Kato K. Hirano K. Miura M. J. Org. Chem. 2017; 82: 10418
33i Zuo Y.-J. Chang X.-T. Hao Z.-M. Zhong C.-M. Org. Biomol. Chem. 2017; 15: 6323
33j Gong T.-J. Yu S.-H. Li K. Su W. Lu X. Xiao B. Fu Y. Chem. Asian J. 2017; 12: 2884

For selected relevant literature on DFT studies of catalytic borylation of alkenes, see:

34a Zhao H. Lin Z. Marder TB. J. Am. Chem. Soc. 2006; 128: 15637
34b Lam KC. Lin Z. Marder TB. Organometallics 2007; 26: 3149
34c Dang L. Zhao H. Lin Z. Marder TB. Organometallics 2007; 26: 2824
34d Dang L. Zhao H. Lin Z. Marder TB. Organometallics 2008; 27: 1178
34e Zhao H. Dang L. Marder TB. Lin Z. J. Am. Chem. Soc. 2008; 130: 5586
34f Dang L. Lin Z. Marder TB. Organometallics 2008; 27: 4443
34g Kleeberg C. Dang L. Lin Z. Marder TB. Angew. Chem. Int. Ed. 2009; 48: 5350
34h Tan D.-H. Lin E. Ji W.-W. Zeng Y.-F. Fan W.-X. Li Q. Gao H. Wang H. Adv. Synth. Catal. 2018; 360: 1032

35a Yang C.-T. Zhang Z.-Q. Tajuddin H. Wu C.-C. Liang J. Liu J.-H. Fu Y. Czyzewska M. Steel PG. Marder TB. Liu L. Angew. Chem. Int. Ed. 2012; 51: 528
35b Xu Z.-Y. Jiang Y.-Y. Su W. Yu H.-Z. Fu Y. Chem. Eur. J. 2016; 22: 14611

36a Yuan W. Zhang X. Yu Y. Ma S. Chem. Eur. J. 2013; 19: 7193
36b Meng F. McGrath KP. Hoveyda AH. Nature 2014; 513: 367

37a Chen J.-B. Jia Y.-X. Org. Biomol. Chem. 2017; 15: 3550
37b Kubota K. Hayama K. Iwamoto H. Ito H. Angew. Chem. Int. Ed. 2015; 54: 8809
37c Kubota K. Watanabe Y. Ito H. Adv. Synth. Catal. 2016; 358: 2379
37d Kubota K. Jin M. Ito H. Organometallics 2016; 35: 1376

38a Isegawa M. Sameera WM. C. Sharma AK. Kitanosono T. Kato M. Kobayashi S. Morokuma K. ACS Catal. 2017; 7: 5370
38b Zhu L. Kitanosono T. Xu P. Kobayashi S. Chem. Commun. 2015; 51: 11685

For selected recent methodological and mechanical investigations on the hydrocupration of alkenes, see:

39a Gribble MW. Pirnot MT. Bandar JS. Liu RY. Buchwald SL. J. Am. Chem. Soc. 2017; 139: 2192
39b Liang T. Jiang L. Gan M. Su X. Li Z. Chin. J. Org. Chem. 2017; 37: 3096
39c Zhou Y. Bandar JS. Liu RY. Buchwald SL. J. Am. Chem. Soc. 2018; 140: 606
39d Yang Y. Shi S.-L. Niu D. Liu P. Buchwald SL. Science 2015; 349: 62
39e Kim H. Yun J. Adv. Synth. Catal. 2010; 352: 1881

40 Won J. Noh D. Yun J. Lee JY. J. Phys. Chem. A 2010; 114: 12112
41 Schmid SC. Van Hoveln R. Rigoli JW. Schomaker JM. Organometallics 2015; 34: 4164
42 Xi Y. Hartwig JF. J. Am. Chem. Soc. 2017; 139: 12758
43 Lu G. Liu RY. Yang Y. Fang C. Lambrecht DS. Buchwald SL. Liu P. J. Am. Chem. Soc. 2017; 139: 16548

For selected examples on background reactions in alkene hydroboration, see:

44a Mömming CM. Frömel S. Kehr G. Fröhlich R. Grimme S. Erker G. J. Am. Chem. Soc. 2009; 131: 12280
44b Rucker RP. Whittaker AM. Dang H. Lalic G. J. Am. Chem. Soc. 2012; 134: 6571
44c Bailey JO. Singleton DA. J. Am. Chem. Soc. 2017; 139: 15710
44d Jin S. Nguyen VT. Dang HT. Nguyen DP. Arman HD. Larionov OV. J. Am. Chem. Soc. 2017; 139: 11365
44e Juhl M. Laursen SL. R. Huang Y. Nielsen DU. Daasbjerg K. Skrydstrup T. ACS Catal. 2017; 7: 1392
44f Rarig R.-AF. Nelson JM. Vedejs E. J. Org. Chem. 2017; 82: 12757
44g Nagashima Y. Sasaki K. Suto T. Sato T. Chida N. Chem. Asian J. 2018; 13: 1024
44h Sanzone JR. Hu CT. Woerpel KA. J. Am. Chem. Soc. 2017; 139: 8404
44i Meyer D. Renaud P. Angew. Chem. Int. Ed. 2017; 56: 10858

For selected examples on NHC activation of diboron compounds, see:

45a Lee K.-S. Zhugralin AR. Hoveyda AH. J. Am. Chem. Soc. 2009; 131: 7253
45b Wen K. Chen J. Gao F. Bhadury PS. Fan E. Sun Z. Org. Biomol. Chem. 2013; 11: 6350
45c Palau-Lluch G. Sanz X. La Cascia E. Civit MG. Miralles N. Cuenca AB. Fernández E. Pure Appl. Chem. 2015; 87: 181
45d Pietsch S. Neeve EC. Apperley DC. Bertermann R. Mo F. Qiu D. Cheung MS. Dang L. Wang J. Radius U. Lin Z. Kleeberg C. Marder TB. Chem. Eur. J. 2015; 21: 7082
45e Eichhorn AF. Kuehn L. Marder TB. Radius U. Chem. Commun. 2017; 53: 11694
45f Eck M. Würtemberger-Pietsch S. Eichhorn A. Berthel JH. J. Bertermann R. Paul US. D. Schneider H. Friedrich A. Kleeberg C. Radius U. Marder TB. Dalton Trans. 2017; 46: 3661

For selected examples on the radical mechanism of the borylation of alkenes, see:

46a Iwamoto H. Akiyama S. Hayama K. Ito H. Org. Lett. 2017; 19: 2614
46b Cui J. Wang H. Song J. Chi X. Meng L. Liu Q. Zhang D. Dong Y. Liu H. Org. Biomol. Chem. 2017; 15: 8508
46c Ren S.-C. Zhang F.-L. Qi J. Huang Y.-S. Xu A.-Q. Yan H.-Y. Wang Y.-F. J. Am. Chem. Soc. 2017; 139: 6050
46d Zhang L. Jiao L. Chem. Sci. 2018; 9: 2711

47 Kumar RN. Meshram HM. Tetrahedron Lett. 2011; 52: 1003
48 Luo Y. Roy ID. Madec AG. E. Lam HW. Angew. Chem. Int. Ed. 2014; 53: 4186

49a Chen I.-H. Yin L. Itano W. Kanai M. Shibasaki M. J. Am. Soc. Chem. 2009; 131: 11664
49b Welle A. Cirriez V. Riant O. Tetrahedron 2012; 68: 3435
49c Cho HY. Morken JP. J. Am. Chem. Soc. 2010; 132: 7576
49d Yu Z. Ely RJ. Morken JP. Angew. Chem. 2014; 126: 9786

50 Medina C. Carter KP. Miller M. Clark TB. O’Neil GW. J. Org. Chem. 2013; 78: 9093

51a Ito Y. Sawamura M. Hayashi T. J. Am. Chem. Soc. 1986; 108: 6405
51b Yadav JS. Hossain SkS. Madhu M. Mohapatra DK. J. Org. Chem. 2009; 74: 8822
51c Yadav JS. Rajender V. Rao YG. Org. Lett. 2010; 12: 348
51d Yadav JS. Rao KV. R. Ravindar K. Reddy BV. S. Eur. J. Org. Chem. 2011; 58

52 Fordred PS. Bull SD. Tetrahedron Lett. 2013; 54: 27