Selective Synthesis of 2- and 7-Substituted Indole Derivatives via Chelation-Assisted Metallocarbenoid C–H Bond Functionalization

Daria V. Vorobyeva; Sergey N. Osipov

doi:10.1055/s-0036-1591498

Synthesis, Table of Contents

Synthesis 2018; 50(02): 227-240
DOI: 10.1055/s-0036-1591498

short review

Selective Synthesis of 2- and 7-Substituted Indole Derivatives via Chelation-Assisted Metallocarbenoid C–H Bond Functionalization

Daria V. Vorobyeva

A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov str. 28, 119991 Moscow, Russian Federation Email: osipov@ineos.ac.ru

,

Sergey N. Osipov*

A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov str. 28, 119991 Moscow, Russian Federation Email: osipov@ineos.ac.ru

› Author Affiliations

Abstract

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Abstract

Functionally substituted indole derivatives are important intermediates for the synthesis of new potential drug candidates exhibiting strong bioactivities. Over the past few years, significant progress has been made in the direct C–H functionalization of the indole ring through the usage of metal-catalyzed intermolecular cross-coupling with diazo compounds. Directing group strategy provides a unique possibility for selective insertion of carbenes catalytically generated from diazo compounds into challenging indole C2–H and C7–H bonds. This short review summarizes recent advances in carbenoid functionalization of indole derivatives under chelation-controlled metal catalysis.

1 Introduction

2 Indole C2 Alkylation with α-Diazotized Meldrum’s Acid

3 Indole C2 Alkylation with Diazomalonate Derivatives and Related Compounds

4 Indole C7 Alkylation with Diazomalonates and Related Compounds

5 Tandem Indole C2–H Alkylation/Cyclization

6 Indoline C7 Alkylation with Diazomalonates and Related Compounds

7 Tandem Indoline C7–H Alkylation/Cyclization

8 Conclusion

Key words

indoles - indolines - diazo compounds - carbenoid - C–H functionalization - metal catalysis

Full Text

References

References

1a Kochanowska-Karamyan AJ. Hamann MT. Chem. Rev. 2010; 110: 4489
1b Kaushik NK. Kaushik N. Attri P. Kumar N. Kim CH. Verma AK. Chio EH. Molecules 2013; 18: 6620
1c Somei M. Yamada F. Nat. Prod. Rep. 2005; 22: 73
1d Chen F.-E. Huang J. Chem. Rev. 2005; 105: 4671
1e Trost BM. Brennan MK. Synthesis 2009; 3003

2a Teders M. Pitzer L. Buss S. Glorius F. ACS Catal. 2017; 7: 4053
2b Lal S. Snape TJ. Curr. Med. Chem. 2012; 19: 4828
2c Abdel-Aty AM. J. Pestic. Sci. 2010; 35: 431
2d Ishikura M. Abe T. Choshi T. Hibino S. Nat. Prod. Rep. 2013; 30: 694
2e Yeung KS. Qiu ZL. Xue QF. Fang HQ. Yang Z. Zadjura L. D’Arienzo CJ. Eggers BJ. Riccardi K. Shi PY. Gong YF. Browning MR. Gao Q. Hansel S. Santone K. Lin PF. Meanwell NA. Kadow JF. Bioorg. Med. Chem. Lett. 2013; 23: 198
2f Yeung KS. Qiu ZL. Yin ZW. Trehan A. Fang HQ. Pearce B. Yang Z. Zadjura L. D’Arienzo CJ. Riccardi K. Shi PY. Spicer TP. Gong YF. Browning MR. Hansel S. Santone K. Barker J. Coulter T. Lin PF. Meanwell NA. Kadow JF. Bioorg. Med. Chem. Lett. 2013; 23: 203

3 Shen C. Liu R.-R. Fan R.-J. Li Y.-L. Xu T.-F. Gao J.-R. Jia Y.-X. J. Am. Chem. Soc. 2015; 137: 4936

4a Ping L. Chung DS. Bouffard J. Lee S. Chem. Soc. Rev. 2017; 46: 4299
4b Leitch JA. Bhonoah Y. Frost CG. ACS Catal. 2017; 7: 5618
4c Cacchi S. Fabrizi G. Chem. Rev. 2005; 105: 2873
4d Humphrey GR. Kuethe JT. Chem. Rev. 2006; 106: 2875
4e Bandini M. Eichholzer A. Angew. Chem. Int. Ed. 2009; 48: 9608
4f Patil S. Patil R. Curr. Org. Synth. 2007; 4: 201
4g Bandini M. Melloni A. Tommasi S. Umani-Ronchi A. Synlett 2005; 1199

5a Doyle MP. McKervey M. Ye T. Modern Catalytic Methods for Organic Synthesis with Diazo Compounds: From Cyclopropanes to Ylides. Wiley; New York: 1998
5b Doyle MP. Forbes DC. Chem. Rev. 1998; 98: 911
5c Davies HM. L. Manning JR. Nature (London) 2008; 451: 417
5d Doyle MP. Duffy R. Ratnikov M. Zhou L. Chem. Rev. 2010; 110: 704

6a Muthusamy S. Gunanathan C. Babu SA. Suresh E. Dastidar P. Chem. Commun. 2002; 824
6b Gibe R. Kerr MA. J. Org. Chem. 2002; 67: 6247
6c Muthusamy S. Gnanaprakasam B. Tetrahedron Lett. 2008; 49: 475
6d DeAngelis A. Shurtleff VW. Dmitrenko O. Fox JM. J. Am. Chem. Soc. 2011; 133: 1650
6e Goto T. Natori Y. Takeda K. Nambu H. Hashimoto S. Tetrahedron: Asymmetry 2011; 22: 907
6f Lian Y. Davies HM. L. Org. Lett. 2010; 12: 924
6g Lian Y. Davies HM. L. Org. Lett. 2012; 14: 1934
6h Lian Y. Davies HM. L. J. Am. Chem. Soc. 2010; 132: 440
6i Qiu H. Li M. Jiang L.-Q. Lv F.-P. Zan L. Zhai C.-W. Doyle MP. Hu W.-H. Nat. Chem. 2012; 4: 733

7a Zhang X.-J. Liu S.-P. Yan M. Chin. J. Chem. 2008; 26: 716
7b Johansen MB. Kerr MA. Org. Lett. 2010; 12: 4956
7c Fraile JM. Le Jeune K. Mayoral JA. Ravasiob N. Zaccheria F. Org. Biomol. Chem. 2013; 11: 4327

8 Yadav JS. Reddy BV. S. Satheesh G. Tetrahedron Lett. 2003; 44: 8331
9 Cai Y. Zhu S.-F. Wang G.-P. Zhou Q.-L. Adv. Synth. Catal. 2011; 353: 2939
10 Davies HM. L. Hedley SJ. Chem. Soc. Rev. 2007; 36: 1109
11 Chan W.-W. Yeung S.-H. Zhou Z. Chan AS. C. Yu W.-Y. Org. Lett. 2010; 12: 604
12 Davies HM. L. Venkataramani C. Hansen T. Hopper DW. J. Am. Chem. Soc. 2003; 125: 6462

13a Song G. Wang F. Li X. Chem. Soc. Rev. 2012; 41: 3651
13b Colby DA. Tsai AS. Bergman RG. Ellman JA. Acc. Chem. Res. 2012; 45: 814
13c Zhu C. Wang R. Falck JR. Chem. Asian J. 2012; 7: 1502
13d Kuhl N. Hopkinson MN. Wencel-Delord J. Glorius F. Angew. Chem. Int. Ed. 2012; 51: 10236
13e Neufeldt SR. Sanford MS. Acc. Chem. Res. 2012; 45: 936
13f Kozhushkov SI. Ackermann L. Chem. Sci. 2013; 4: 886
13g Wencel-Delord J. Glorius F. Nat. Chem. 2013; 5: 369
13h Thirunavukkarasu VS. Kozhushkov SI. Ackermann L. Chem. Commun. 2014; 50: 29
13i Ackermann L. Acc. Chem. Res. 2014; 47: 281
13j Kuhl N. Schröder N. Glorius F. Adv. Synth. Catal. 2014; 356: 1443
13k Zhang Y. Jie X. Zhao H. Li G. Su W. Org. Chem. Front. 2014; 1: 843
13l Zhuo CX. Zheng C. You SL. Acc. Chem. Res. 2014; 47: 2558
13m Chen F. Wang T. Jiao N. Chem. Rev. 2014; 114: 8613
13n He R. Huang ZT. Zheng QY. Wang C. Tetrahedron Lett. 2014; 55: 5705
13o Moselage M. Sauermann N. Richter SC. Ackermann L. Angew. Chem. Int. Ed. 2015; 54: 6352

14a Chen Y. Wang F. Zhen W. Li X. Adv. Synth. Catal. 2013; 355: 353
14b Wang N. Li B. Song H. Xu S. Wang B. Chem. Eur. J. 2013; 19: 358
14c Presset M. Oehlrich D. Rombouts F. Molander GA. Org. Lett. 2013; 15: 1528
14d Quiñones N. Seoane A. García-Fandiño R. Mascareñas JL. Gulías M. Chem. Sci. 2013; 4: 2874
14e Li B.-J. Wang H.-Y. Zhu Q.-L. Shi Z.-J. Angew. Chem. Int. Ed. 2012; 51: 3948
14f Zhu C. Falck FR. Chem. Commun. 2012; 48: 1674
14g Tan X. Liu B. Li X. Li B. Xu S. Song H. Wang B. J. Am. Chem. Soc. 2012; 134: 16163
14h Patureau FW. Wencel-Delord J. Glorius F. Aldrichimica Acta 2012; 45: 31
14i Wang Y.-F. Toh KK. Lee J.-Y. Chiba S. Angew. Chem. Int. Ed. 2011; 50: 5927
14j Muralirajan K. Parthasarathy K. Cheng C.-H. Angew. Chem. Int. Ed. 2011; 50: 4169
14k Patureau FW. Besset T. Kuhl N. Glorius F. J. Am. Chem. Soc. 2011; 133: 2154
14l Li X. Zhao M. J. Org. Chem. 2011; 76: 8530
14m Guimond N. Gorelsky SI. Fagnou K. J. Am. Chem. Soc. 2011; 133: 6449
14n Zhang X. Chen D. Zhao M. Zhao J. Jia A. Li X. Adv. Synth. Catal. 2011; 353: 719
14o Wencel-Delord J. Dröge T. Liu F. Glorius F. Chem. Soc. Rev. 2011; 40: 4740
14p Too PC. Wang Y.-F. Chiba S. Org. Lett. 2010; 12: 5688
14q Hyster TK. Rovis T. J. Am. Chem. Soc. 2010; 132: 10565
14r Satoh T. Miura M. Chem. Eur. J. 2010; 16: 11212
14s Chen Z. Wang B. Zhang J. Yu W. Liu Z. Zhang Y. Org. Chem. Front. 2015; 2: 1107

For selected reviews on catalytic C2 functionalization of indoles, see:

15a Seregin IV. Gevorgyan V. Chem. Soc. Rev. 2007; 36: 1173
15b Joucla L. Djakovitch L. Adv. Synth. Catal. 2009; 351: 673
15c Beck EM. Gaunt MJ. Top. Curr. Chem. 2010; 292: 85
15d Cacchi S. Fabrizi G. Chem. Rev. 2011; 111: 215
15e Sandtorv AH. Adv. Synth. Catal. 2015; 357: 2403

16a Jiao L.-Y. Smirnov P. Oestreich M. Org. Lett. 2014; 16: 6020
16b Nishikata T. Abela AR. Huang S. Lipshutz BH. J. Am. Chem. Soc. 2010; 132: 4978
16c Kalyani D. Deprez NR. Desai LV. Sanford MS. J. Am. Chem. Soc. 2005; 127: 7330
16d Shi Z. Li B. Wan X. Cheng J. Fang Z. Cao B. Qin C. Wang Y. Angew. Chem. Int. Ed. 2007; 46: 5554

17a Urones B. Arrays RG. Carretero JC. Org. Lett. 2013; 15: 1120
17b Jiao L.-Y. Oestreich M. Org. Lett. 2013; 15: 5374
17c Song Z. Samanta R. Antonchick AP. Org. Lett. 2013; 15: 5662
17d Pan S. Wakaki T. Ryu N. Shibata T. Chem. Asian J. 2014; 9: 1257
17e Yang D. Mao S. Gao Y.-R. Guo D.-D. Guo S.-H. Li B. Wang Y.-Q. RSC Adv. 2015; 5: 23727

18 Yang X.-F. Hu X.-H. Feng C. Loh T.-P. Chem. Commun. 2015; 51: 2532

19a Shin K. Chang S. J. Org. Chem. 2014; 79: 12197
19b Pan C. Abdukader A. Han J. Cheng Y. Zhu C. Chem. Eur. J. 2014; 20: 3606
19c Hou W. Yang Y. Ai W. Wu Y. Wang X. Zhou B. Li Y. Eur. J. Org. Chem. 2015; 395

20a Kim M. Mishra NK. Park J. Han S. Shin Y. Sharma S. Lee Y. Lee E.-K. Kwak JH. Kim IS. Chem. Commun. 2014; 50: 14249
20b Shin Y. Sharma S. Mishra NK. Han S. Park J. Oh H. Ha J. Yoo H. Jung YH. Kim IS. Adv. Synth. Catal. 2015; 357: 594
20c Chan C.-W. Zhou Z. Yu W.-Y. Adv. Synth. Catal. 2011; 353: 2999

21a Park J. Mishra NK. Sharma S. Han S. Shin Y. Jeong T. Oh JS. Kwak JH. Jung YH. Kim IS. J. Org. Chem. 2015; 80: 1818
21b Sharma S. Shin Y. Mishra NK. Park J. Han S. Jeong T. Oh Y. Lee Y. Choi M. Kim IS. Tetrahedron 2015; 71: 2435

22 Xie W. Li B. Wang B. J. Org. Chem. 2016; 81: 396

23a Pan S. Ryu N. Shibata T. Adv. Synth. Catal. 2014; 356: 929
23b Neufeldt SR. Seigerman CK. Sanford M. Org. Lett. 2013; 15: 2302
23c Premi C. Dixit A. Jain N. Org. Lett. 2015; 17: 2598
23d Zhou X. Yu S. Qi Z. Kong L. Li X. J. Org. Chem. 2016; 81: 4869
23e Jo H. Park J. Choi M. Sharma S. Jeon M. Mishra NK. Jeong T. Han S. Kim IS. Adv. Synth. Catal. 2016; 358: 2714

24a Yi CS. Yun SY. Guzei IA. J. Am. Chem. Soc. 2005; 127: 5782
24b Yi CS. Yun SY. J. Am. Chem. Soc. 2005; 127: 17000
24c Wang X. Tang H.-Y. Feng H.-J. Li Y.-C. Yang Y.-X. Zhou B. J. Org. Chem. 2015; 80: 6238
24d Yang X.-F. Hu X.-H. Loh T.-P. Org. Lett. 2015; 17: 1481

25 Chan W.-W. Lo S.-F. Zhou Z. Yu W.-Y. J. Am. Chem. Soc. 2012; 134: 13565
26 Hu F. Xia Y. Ma C. Zhang Y. Wang J. Chem. Commun. 2015; 51: 7986
27 Xia Y. Liu Z. Feng S. Zhang Y. Wang J. J. Org. Chem. 2015; 80: 223

28a Zhao D. Kim JH. Stegemann L. Strassert CA. Glorius F. Angew. Chem. Int. Ed. 2015; 54: 4508
28b Liu X.-G. Zhang S.-S. Wu J.-Q. Li Q. Wang H. Tetrahedron Lett. 2015; 56: 4093

For reviews, see:

29a Barluenga J. Valdés C. Angew. Chem. Int. Ed. 2011; 50: 7486
29b Shao Z.-H. Zhang H.-B. Chem. Soc. Rev. 2012; 41: 560
29c Xiao Q. Zhang Y. Wang J.-B. Acc. Chem. Res. 2013; 46: 236
29d Liu Z.-X. Wang J.-B. J. Org. Chem. 2013; 78: 10024
29e Xia Y. Zhang Y. Wang J.-B. ACS Catal. 2013; 3: 2586

30 Shi J. Yan Y. Li Q. Xu HE. Yi W. Chem. Commun. 2014; 50: 6483

31a Lamotte Y. Martres P. Faucher N. Laroze A. Grillot D. Ancellin N. Saintillan Y. Beneton V. Gampe RT. Jr. Bioorg. Med. Chem. Lett. 2010; 20: 1399
31b Choi JH. Banks AS. Kamenecka TM. Busby SA. Chalmers MJ. Kumar N. Kuruvilla DS. Shin Y. He Y. Bruning JB. Marciano DP. Cameron MD. Laznik D. Jurczak MJ. Schurer SC. Vidovic D. Shulman GI. Spiegelman BM. Griffin PR. Nature (London) 2011; 477: 477

32 Wan K. Li Z. Qu X. Wang F. Wang L. Catalysts 2016; 6: 89

33a Kirk KL. J. Fluorine Chem. 2006; 127: 1013
33b Müller K. Faeh C. Diederich F. Science (Washington, D. C.) 2007; 317: 1881
33c Hagmann WK. J. Med. Chem. 2008; 51: 4359
33d O’Hagan D. J. Fluorine Chem. 2010; 131: 1071
33e Lundgren RJ. Stradiotto M. Angew. Chem. Int. Ed. 2010; 49: 9322
33f Salwiczek M. Nyakatura EK. Gerling UI. M. Ye S. Koksch B. Chem. Soc. Rev. 2012; 41: 2135
33g Ojima I. J. Org. Chem. 2013; 78: 6358
33h Wang J. Sánchez-Roselló M. Aceña JL. del Pozo A. Sorochinsky E. Fustero S. Soloshonok VA. Liu H. Chem. Rev. 2014; 114: 2432

For selected paper see:

34a Shi G. Xu Y. J. Chem. Soc., Chem. Commun. 1989; 607
34b Shi G. Xu Y. Xu M. Tetrahedron 1991; 47: 1629
34c Osipov SN. Sewald N. Burger K. Kolomiets AF. Fokin AV. Tetrahedron Lett. 1996; 37: 615
34d Jiang B. Zhang Z. Luo Z. Org. Lett. 2002; 4: 2453
34e Mueller P. Grass S. Shahi SP. Bernardinelli G. Tetrahedron 2004; 60: 4755
34f Pang W. Zhu S. Jianga H. Zhu S. Tetrahedron 2006; 62: 11760
34g Vorobyeva DV. Mailyan AK. Peregudov AS. Karimova NM. Vasilyeva TP. Bushmarinov IS. Bruneau C. Dixneuf PH. Osipov SN. Tetrahedron 2011; 67: 3524
34h Swenson AK. Higgins KE. Brewer MG. Coleman MG. Brennessel WW. Org. Biomol. Chem. 2012; 10: 7483
34i Sang R. Shi M. Yang H.-B. Tetrahedron Lett. 2013; 54: 3591
34j Rivilla I. Gomez-Emeterio BP. Fructos MR. Diaz-Requejo MM. Perez PJ. Organometallics 2011; 30: 2855
34k Mailyan AK. Krylov IM. Bruneau C. Dixneuf PH. Osipov SN. Synlett 2011; 2321
34l Mailyan AK. Peregudov AS. Dixneuf PH. Bruneau C. Osipov SN. J. Org. Chem. 2012; 77: 8518
34m Mailyan AK. Krylov IM. Bruneau C. Dixneuf PH. Osipov SN. Eur. J. Org. Chem. 2013; 5353
34n Yagafarova IE. Vorobyeva DV. Peregudov AS. Osipov SN. Eur. J. Org. Chem. 2014; 2480

35 Tsyshchuk IE. Vorobyeva DV. Peregudov AS. Osipov SN. Eur. J. Org. Chem. 2015; 4950

36a Pototschnig G. Maulide N. Schnürch M. Chem. Eur. J. 2017; 23: 9206
36b Wang S. Chen S.-Y. Yu X.-Q. Chem. Commun. 2017; 53: 3165
36c Chirila PG. Whiteoak CJ. Dalton Trans. 2017; 46: 9721

37a Ershov VV. Nikiforov GA. De Jonge CR. H. I. Studies in Organic Chemistry: Quinonediazides . Elsevier; Amsterdam: 1981
37b Griesbeck AG. Zimmermann E. In Science of Synthesis . Vol. 28. Griesbeck AG. Thieme; Stuttgart: 2000: 807-830

38a Dao H.-T. Baran PS. Angew. Chem. Int. Ed. 2014; 53: 14382
38b Mori H. Tando I. Tanaka H. Macromolecules 2010; 43: 7011
38c Wallraff GM. Hinsberg WD. Chem. Rev. 1999; 99: 1801

39 Zhang S.-S. Jiang C.-Y. Wu J.-Q. Liu X.-G. Li Q. Huang Z.-S. Li D. Wang H. Chem. Commun. 2015; 51: 10240
40 Wang L. Li Z. Qu X. Peng W.-M. Hu S.-Q. Wang H.-B. Tetrahedron Lett. 2015; 56: 6214
41 Jiang H. Gao S. Xu J. Wu X. Lin A. Yao H. Adv. Synth. Catal. 2016; 358: 188
42 Mishra NK. Choi M. Jo H. Oh Y. Sharma S. Han SH. Jeong T. Han S. Lee S.-Y. Kim IS. Chem. Commun. 2015; 51: 17229

43a Mizuta M. Seio K. Miyata K. Sekine M. J. Org. Chem. 2007; 72: 5046
43b Bandurco VT. Wong EM. Levine SD. Hajos ZG. J. Med. Chem. 1981; 24: 1455
43c Hammer H. Winterfeldt E. Tetrahedron 1981; 37: 3609
43d Kato M. Nishino S. Ito K. Yamakuni H. Takasugi H. Chem. Pharm. Bull. 1994; 42: 2556
43e Liu J. Shen M. Zhang Y. Li G. Khodabocus A. Rodriguez S. Qu B. Farina V. Senanayake H. Lu BZ. Org. Lett. 2006; 8: 3573
43f Nukamura I. Sato Y. Terada M. J. Am. Chem. Soc. 2009; 131: 4198
43g Wang Z.-J. Yang J.-G. Bao W. Org. Lett. 2010; 12: 3034
43h Sharp PP. Banwell MG. Renner J. Lohmann K. Willis AC. Org. Lett. 2013; 15: 2616

44 Zhang Y. Zheng J. Cui S. J. Org. Chem. 2014; 79: 6490
45 Chen X. Hu X. Bai S. Deng Y. Jiang H. Zeng W. Org. Lett. 2016; 18: 192

46a Kamata J. Okada T. Kotake Y. Niijima J. Nakamura K. Uenaka T. Yamaguchi A. Tsukahara K. Nagasu T. Koyanagi N. Kitoh K. Yoshimatsu K. Yoshino H. Sugumi H. Chem. Pharm. Bull. 2004; 52: 1071
46b Wright WB. Jr. Brabander HJ. J. Med. Chem. 1968; 11: 1164

47 Wu J.-Q. Yang Z. Zhang S.-S. Jiang C.-Y. Li Q. Huang Z.-S. Wang H. ACS Catal. 2015; 5: 6453
48 Rathore KS. Harode M. Katukojvala S. Org. Biomol. Chem. 2014; 12: 8641

For selected examples, see:

49a Broggini G. Beccalli EM. Fasana A. Gazzola S. Beilstein J. Org. Chem. 2012; 8: 1730
49b Lane BS. Sames D. Org. Lett. 2004; 6: 2897
49c Wang X. Lane BS. Sames D. J. Am. Chem. Soc. 2005; 127: 4996
49d Lane BS. Brown MA. Sames D. J. Am. Chem. Soc. 2005; 127: 8050
49e Deprez NR. Kalyani D. Krause A. Sanford MS. J. Am. Chem. Soc. 2006; 128: 4972
49f Touré BB. Lane BS. Sames D. Org. Lett. 2006; 8: 1979
49g Stuart DR. Villemure E. Fagnou K. J. Am. Chem. Soc. 2007; 129: 12072
49h Yang S.-D. Sun C.-L. Fang Z. Li B.-J. Li Y.-Z. Shi Z.-J. Angew. Chem. Int. Ed. 2008; 47: 1473
49i Jiao L. Bach T. J. Am. Chem. Soc. 2011; 133: 12990
49j Zhou B. Yang Y. Li Y. Chem. Commun. 2012; 48: 5163
49k Pan S. Ryu N. Shibata T. J. Am. Chem. Soc. 2012; 134: 17474
49l Jiao L. Herdtweck E. Bach T. J. Am. Chem. Soc. 2012; 134: 14563
49m Zhou B. Yang Y. Lin S. Li Y. Adv. Synth. Catal. 2013; 355: 360
49n Ding Z. Yoshikai N. Angew. Chem. Int. Ed. 2012; 51: 4698
49o Kanyiva KS. Nakao Y. Hiyama T. Heterocycles 2007; 72: 677
49p Schipper DJ. Hutchinson M. Fagnou K. J. Am. Chem. Soc. 2010; 132: 6910
49q Yang L. Zhang G. Huang H. Adv. Synth. Catal. 2014; 356: 1509

50a Chatani N. Yorimitsu S. Asaumi T. Kakiuchi F. Murai S. J. Org. Chem. 2002; 67: 7557
50b Jiao L. Oestreich M. Chem. Eur. J. 2013; 19: 10845

51 Ai W. Yang X. Wu Y. Wang X. Li Y. Yang Y. Zhou B. Chem. Eur. J. 2014; 20: 17653
52 Anzalone AV. Wang TY. Chen Z. Cornish VW. Angew. Chem. Int. Ed. 2013; 52: 650
53 Iagafarova IE. Vorobyeva DV. Loginov DA. Peregudov AS. Osipov SN. Eur. J. Org. Chem. 2017; 840
54 Zhou T. Lia B. Wang B. Chem. Commun. 2016; 52: 14117