Synthetic Strategy for Multisubstituted Fused Furan Compounds Using Main-Group Metal Reagents

Hayato Tsuji; Laurean Ilies; Eiichi Nakamura

doi:10.1055/s-0034-1378232

Synlett, Inhaltsverzeichnis

Synlett 2014; 25(15): 2099-2110
DOI: 10.1055/s-0034-1378232

account

Synthetic Strategy for Multisubstituted Fused Furan Compounds Using Main-Group Metal Reagents

Hayato Tsuji*

^aDepartment of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Fax: +81(3)58414367 eMail: tsuji@chem.s.u-tokyo.ac.jp eMail: nakamura@chem.s.u-tokyo.ac.jp

^bJapan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan Fax: +81(3)58414367 eMail: tsuji@chem.s.u-tokyo.ac.jp eMail: nakamura@chem.s.u-tokyo.ac.jp

,

Laurean Ilies

^aDepartment of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Fax: +81(3)58414367 eMail: tsuji@chem.s.u-tokyo.ac.jp eMail: nakamura@chem.s.u-tokyo.ac.jp

,

Eiichi Nakamura*

^aDepartment of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Fax: +81(3)58414367 eMail: tsuji@chem.s.u-tokyo.ac.jp eMail: nakamura@chem.s.u-tokyo.ac.jp

› Institutsangaben

Abstract

Alle Artikel dieser Rubrik

Abstract

In this account, we summarize our recent studies on the synthesis of multisubstituted furan compounds. The synthetic strategy relies on the electrophilic cyclization of o-hydroxy(alkynyl)arenes by using main-group metal reagents. For example, zinc salts have been found to mediate the cyclization of o-alkynylphenols to form thermally stable yet chemically reactive β-zincio intermediates (‘synthetic modules’) that serve as platforms for the syntheses of a series of analogues having the same core structural motif (the ‘molecular library’). This modular approach is applicable to the synthesis of new benzofurans and benzodifurans and their homologues, and allows us to study the photophysical and semiconducting properties of these products systematically. We have similarly developed a synthesis of benzotrifurans by a cesium hydroxide-mediated tandem S_NAr/triple-cyclization reaction, as well as a synthesis of trisubstituted furans by indium-catalyzed cycloisomerization of α-propargyl β-keto esters.

1 Introduction

2 Modular Approach for the Synthesis of Fused Furan Derivatives Using Zinc Salt

2.1 Zinc-Mediated Cyclization Reaction and Synthesis of Functionalized Benzofurans

2.2 Selective Syntheses of Benzodifurans Based on the Modular Method

2.3 Homologues of BDF: Naphtho- (NDF) and Anthradifurans (ADF)

3. Syntheses of Other Furans

3.1 Cesium Hydroxide-Promoted One-Pot Reaction for the Synthesis of Benzotrifurans

3.2 Indium-Catalyzed Cycloisomerization Reaction for the Synthesis of Multisubstituted Furans

4 Conclusions

Key words

Furans - fused-ring systems - cyclization - zinc - indium

Volltext

Referenzen

References

For selected reviews on DOS, see:

1a Schreiber SL. Science 2000; 287: 1964
1b Arya P, Chou DT. H, Baek M.-G. Angew. Chem. Int. Ed. 2001; 40: 339
1c Burke MD, Berger EM, Schreiber SL. Science 2003; 302: 613
1d Tan DS. Nat. Chem. Biol. 2005; 1: 74
1e Itami K, Yoshida J.-i. Bull. Chem. Soc. Jpn. 2006; 79: 811
1f Itami K, Yoshida J.-i. Chem. Eur. J. 2006; 12: 3966
1g Sunderhaus JD, Martin SF. Chem. Eur. J. 2009; 15: 1300

For modular syntheses of polymers and coordination compounds, see:

2a Yoshizawa M, Klosterman JK, Fujita M. Angew. Chem. Int. Ed. 2009; 48: 3418
2b Lin W, Rieter WJ, Taylor KM. L. Angew. Chem. Int. Ed. 2009; 48: 650

For modular syntheses of organic compounds, see:

3a Tykwinski RR, Gholami M, Eisler S, Zhao Y, Melin F, Echegoyen L. Pure Appl. Chem. 2008; 80: 621
3b Nakamura M. Pure Appl. Chem. 2006; 78: 425
3c Tsuji H. Yuki Gosei Kagaku Kyokaishi 2010; 68: 1057
3d Storer RI, Aciro C, Jones LH. Chem. Soc. Rev. 2011; 40: 2330

For reactions of alkenes, see:

4a Kubota K, Nakamura E. Angew. Chem. Int. Ed. Engl. 1997; 36: 2491
4b Lorthiois E, Marek I, Normant JF. J. Org. Chem. 1998; 63: 566
4c Rodriguez AL, Bunlaksananusorn T, Knochel P. Org. Lett. 2000; 2: 3285
4d Pei T, Widenhoefer RA. J. Am. Chem. Soc. 2001; 123: 11290
4e Yao X, Li C.-J. J. Am. Chem. Soc. 2004; 126: 6884
4f Nakamura M, Hatakeyama T, Hara K, Nakamura E. J. Am. Chem. Soc. 2003; 125: 6362
4g Nakamura M, Hatakeyama T, Nakamura E. J. Am. Chem. Soc. 2004; 126: 11820

For intermolecular reactions of alkynes, see:

5a Nakamura M, Liang C, Nakamura E. Org. Lett. 2004; 6: 2015
5b Nakamura M, Fujimoto T, Endo K, Nakamura E. Org. Lett. 2004; 6: 4837
5c Nakamura M, Endo K, Nakamura E. J. Am. Chem. Soc. 2003; 125: 13002
5d Nakamura M, Endo K, Nakamura E. Org. Lett. 2005; 7: 3279
5e Nakamura M, Endo K, Nakamura E. Adv. Synth. Catal. 2005; 347: 1681
5f Endo K, Hatakeyama T, Nakamura M, Nakamura E. J. Am. Chem. Soc. 2007; 129: 5264
5g Tsuji H, Fujimoto T, Endo K, Nakamura M, Nakamura E. Org. Lett. 2008; 10: 1219
5h Fujimoto T, Endo K, Tsuji H, Nakamura M, Nakamura E. J. Am. Chem. Soc. 2008; 130: 4492
5i Tsuji H, Yamagata K.-i, Fujimoto T, Nakamura E. J. Am. Chem. Soc. 2008; 130: 7792
5j Yoshikai N, Zhang S.-L, Yamagata K.-i, Tsuji H, Nakamura E. J. Am. Chem. Soc. 2009; 131: 4099
5k Tsuji H, Tanaka I, Endo K, Yamagata K, Nakamura M, Nakamura E. Org. Lett. 2009; 11: 1845

For intramolecular reactions of alkynes, see:

6a Tsuji H, Yamagata K.-i, Itoh Y, Endo K, Nakamura M, Nakamura E. Angew. Chem. Int. Ed. 2007; 46: 8060
6b Itoh Y, Tsuji H, Yamagata K.-i, Endo K, Tanaka I, Nakamura M, Nakamura E. J. Am. Chem. Soc. 2008; 130: 17161

For reviews on transition metal-catalyzed benzofuran synthesis, see:

7a Cacchi S, Fabrizi G, Goggiamani A. Org. Biomol. Chem. 2011; 9: 641
7b Zeni G, Larock RC. Chem. Rev. 2006; 106: 4644

For recent examples of transition metal-catalyzed benzofuran syntheses, see:

8a Chen C.-Y, Dormer PG. J. Org. Chem. 2005; 70: 6964
8b Nakamura I, Mizushima Y, Yamamoto Y. J. Am. Chem. Soc. 2005; 127: 15022
8c Carril M, SanMartin R, Tellitu I, Domínguez E. Org. Lett. 2006; 8: 1467
8d Lu B, Wang B, Zhang Y, Ma D. J. Org. Chem. 2007; 72: 5337
8e Anderson KW, Ikawa T, Tundel RE, Buchwald SL. J. Am. Chem. Soc. 2006; 128: 10694
8f Tsuchikama K, Hashimoto Y, Endo K, Shibata T. Adv. Synth. Catal. 2009; 351: 2850
8g Majumdar KC, Chattopadhyay B, Chakravorty S. Synthesis 2009; 674
8h Wang J.-R, Manabe K. J. Org. Chem. 2010; 75: 5340
8i Maimone TJ, Buchwald SL. J. Am. Chem. Soc. 2010; 132: 9990
8j Hirano K, Satoh T, Miura M. Org. Lett. 2011; 13: 2395
8k Hachiya H, Hirano K, Satoh T, Miura M. Org. Lett. 2011; 13: 3076
8l Shibata T, Hashimoto Y.-k, Otsuka M, Tsuchikama K, Endo K. Synlett 2011; 2075
8m Wang S, Li P, Yu L, Wang L. Org. Lett. 2011; 13: 5968
8n Matsuda N, Hirano K, Satoh T, Miura M. J. Org. Chem. 2012; 77: 617
8o Kuram MR, Bhanuchandra M, Sahoo AK. Angew. Chem. Int. Ed. 2013; 52: 4607
8p Shigeta M, Watanabe J, Konishi G. Tetrahedron Lett. 2013; 54: 1761

For recent examples of other methods, see:

9a Kumar MP, Liu R.-S. J. Org. Chem. 2006; 71: 4951
9b Takeda N, Miyata O, Naito T. Eur. J. Org. Chem. 2007; 1491
9c Kobatake T, Fujino D, Yoshida S, Yorimitsu H, Oshima K. J. Am. Chem. Soc. 2010; 132: 11838
9d Pei T, Chen C.-y, DiMichele L, Davies IW. Org. Lett. 2010; 12: 4972
9e Schevenels F, Markó IE. Org. Lett. 2012; 14: 1298
9f Singh FV, Wirth T. Synthesis 2012; 44: 1171

For recent examples of multiple-cyclization reactions, see:

10a Yue D, Yao T, Larock RC. J. Org. Chem. 2005; 70: 10292
10b Liang Z, Ma S, Yu J, Xu R. J. Org. Chem. 2007; 72: 9219
10c Liang Z, Ma S, Yub J, Xu R. Tetrahedron 2007; 63: 12877
10d Matsuura Y, Tanaka Y, Akita M. J. Organomet. Chem. 2009; 694: 1840
10e Gay RM, Manarin F, Schneider CC, Barancelli DA, Costa MD, Zeni G. J. Org. Chem. 2010; 75: 5701
10f Yi C, Blum C, Lehmann M, Keller S, Liu S.-X, Frei G, Neels A, Hauser J, Schürch S, Decurtins S. J. Org. Chem. 2010; 75: 3350
10g Kundu D, Samim M, Majee A, Hajra A. Chem. Asian J. 2011; 6: 406
10h Moussallem C, Gohier F, Mallet C, Allain M, Frère P. Tetrahedron 2012; 68: 8617

11a Brown RC. D. Angew. Chem. Int. Ed. 2005; 44: 850
11b Bunz UH. F. Angew. Chem. Int. Ed. 2010; 49: 5037
11c Heterocycles in Natural Product Synthesis . Majumdar KC, Chattopadhyay SK. Wiley; Chichester: 2011
11d Handbook of Heterocyclic Chemistry. Katritzky AR, Ramsden CA, Joule JA, Zhdankin VV. Elsevier; Amsterdam: 2010. 3rd ed.
11e Simonetti SO, Larghi EL, Bracca AB. J, Kaufman TS. Nat. Prod. Rep. 2013; 30: 941

For examples, see:

12a Heltzel CE, Gunatilaka AA. L, Glass TE, Kingston DG. I. Tetrahedron 1993; 49: 6757
12b Chambers JJ, Kurrasch-Orbaugh DM, Parker MA, Nichols DE. J. Med. Chem. 2001; 44: 1003

13a Lipshutz BH. Chem. Rev. 1986; 86: 795
13b Kirsch SF. Org. Biomol. Chem. 2006; 4: 2076

14 For an example of postfunctionalization of fused furan compounds, see: Li Y, Waser J. Beilstein J. Org. Chem. 2013; 9: 1763

15a Nakamura M, Ilies L, Otsubo S, Nakamura E. Angew. Chem. Int. Ed. 2006; 45: 944
15b Nakamura M, Ilies L, Otsubo S, Nakamura E. Org. Lett. 2006; 8: 2803

16 Kraemer G, Spilker A. Ber. Dtsch. Chem. Ges 1890; 23: 78
17 Stoermer J. Ber. Dtsch. Chem. Ges. 1897; 30: 1700
18 Knochel P, Singer RD. Chem. Rev. 1993; 93: 2117 ; and references therein
19 Nakamura E, Aoki S, Sekiya K, Oshino H, Kuwajima I. J. Am. Chem. Soc. 1987; 109: 8056
20 Yoshikai N, Miura K, Nakamura E. Adv. Synth. Catal. 2009; 351: 1014
21 Yoshikai N, Zhang S.-L, Nakamura E. J. Am. Chem. Soc. 2009; 130: 12862
22 Matsuzawa S, Horiguchi Y, Nakamura E, Kuwajima I. Tetrahedron 1989; 45: 349

23a Tsuji H, Mitsui C, Ilies L, Sato Y, Nakamura E. J. Am. Chem. Soc. 2007; 129: 11902
23b Tsuji H, Mitsui C, Sato Y, Nakamura E. Adv. Mater. (Weinheim, Ger.) 2009; 21: 3776

For early studies on the semiconducting properties of furans and their applications, see:

24a Zhang L.-Z, Chen C.-W, Lee C.-C, Luh T.-Y. Chem. Commun. 2002; 2336
24b Wu C.-C, Hung W.-Y, Liu T.-L, Zhang L.-Z, Luh T.-Y. J. Appl. Phys. 2003; 93: 5465
24c Anderson S, Taylor PN, Verschoor GL. B. Chem. Eur. J. 2004; 10: 518
24d Miyata Y, Nishinaga T, Komatsu K. J. Org. Chem. 2005; 70: 1147
24e Miyata Y, Terayama M, Minari T, Nishinaga T, Nemoto T, Isoda S, Komatsu K. Chem. Asian J. 2007; 2: 1492

For studies on photophysical properties and structures of fused furans, see:

25a Abdul-Aziz M, Auping JV, Meador MA. J. Org. Chem. 1995; 60: 1303
25b Takahashi K, Kobayashi K. J. Org. Chem. 2000; 65: 2577
25c Kang SK, Park KK, Kim WC, Kim S.-H. Acta Crystallogr., Sect. E 2004; 60: o1195
25d Gu JM, Hu X.-R, Xu W.-M. Acta Crystallogr., Sect. E 2005; 61: o3674

26 Handbook of Thiophene-Based Materials: Applications in Organic Electronics and Photonics. Perepichka IF, Perepichka DF. Wiley; Chichester: 2009

27a Japp FR, Meldrum AN. J. Chem. Soc., Trans. 1899; 75: 1035

The reaction was later proved to afford a sizable amount of regioisomeric 1,2,7,8-tetraarylbenzo[1,2-b:4,3-b']difuran as a byproduct; see:

27b le Fèvre RJ. W, Taylor CR, Whittem RN. J. Chem. Soc. 1948; 1992
27c Dischendorfer O, Limontschew W. Monatsh. Chem. 1949; 80: 58
27d Domschke G. Chem. Ber. 1966; 99: 930

28 Cacchi S, Fabrizi G, Goggiomani A. Heterocycles 2002; 56: 613
29 Note that cyclization itself takes place without prior deprotonation with butyllithium to afford the p-BDF 4; however, it results in a lower yield.

30a Negishi E, King AO, Okukado N. J. Org. Chem. 1977; 42: 1821
30b Negishi E, Takahashi T, King AO. Org. Synth. 1985; 66: 67
30c Negishi E. Angew. Chem. Int. Ed. 2011; 50: 6738

31 Yamamoto T, Nishiyama M, Koie Y. Tetrahedron Lett. 1998; 39: 2367
32 Fu GC. Acc. Chem. Res. 2008; 41: 1555
33 Dai C, Fu GC. J. Am. Chem. Soc. 2001; 123: 2719

34a Tsuji H, Favier GM. O, Mitsui C, Lee S, Hashizume D, Nakamura E. Chem. Lett. 2011; 40: 576
34b Mitsui C, Tanaka H, Tsuji H, Nakamura E. Chem. Asian J. 2011; 6: 2296
34c Mitsui C, Tsuji H, Sato Y, Nakamura E. Chem. Asian J. 2012; 7: 1443

35 Tsuji H, Mitsui C, Sato Y, Nakamura E. Heteroat. Chem. 2011; 22: 316

36a Mitsui C, Soeda J, Miwa K, Tsuji H, Takeya J, Nakamura E. J. Am. Chem. Soc. 2012; 134: 5448
36b Tsuji H, Shoyama K, Nakamura E. Chem. Lett. 2012; 41: 957

37 Mitsui, C.; Tsuji, H.; Nakamura, E. unpublished results.

For examples of solution-processable organic materials, see:

38a Minemawari H, Yamada T, Matsui H, Tsutsumi J, Haas S, Chiba R, Kumai R, Hasegawa T. Nature 2011; 475: 364
38b Okamoto T, Mitsui C, Yamagishi M, Nakahara K, Soeda J, Hirose Y, Miwa K, Sato H, Yamano A, Matsushita T, Uemura T, Takeya J. Adv. Mater. (Weinheim, Ger.) 2013; 25: 6392

39 Tsuji H, Cantagrel G, Ueda Y, Chen T, Wan L.-J, Nakamura E. Chem. Asian J. 2013; 8: 2377

40a Brown BR, Somerfield GA, Weitzman PD. J. J. Chem. Soc. 1958; 4305
40b Li Y, Lampkins AJ, Baker MB, Sumpter BG, Huang J, Abboud KA, Castellano RK. Org. Lett. 2009; 11: 4314

41 Tsuji H, Yamagata K.-i, Ueda Y, Nakamura E. Synlett 2011; 1015
42 Frost CG, Hartley JP, Griffin D. Tetrahedron Lett. 2002; 43: 4789

For nitrogen-containing heterocyclic compounds, see:

43a Tsuji H, Yokoi Y, Mitsui C, Ilies L, Sato Y, Nakamura E. Chem. Asian J. 2009; 4: 655
43b Tsuji H, Yokoi Y, Sato Y, Tanaka H, Nakamura E. Chem. Asian J. 2011; 6: 2005
43c Tsuji H, Yokoi Y, Furukawa S, Nakamura E. Heterocycles 2014; in press; doi:10.3987/COM-14-S(K)16

For modular approaches to the synthesis of phosphorus-containing heterocyclic compounds, see:

44a Tsuji H, Sato K, Ilies L, Itoh Y, Sato Y, Nakamura E. Org. Lett. 2008; 10: 2263
44b Tsuji H, Sato K, Sato Y, Nakamura E. J. Mater. Chem. 2009; 19: 3364
44c Tsuji H, Sato K, Sato Y, Nakamura E. Chem. Asian J. 2010; 5: 1294
44d Kojima T, Furukawa S, Tsuji H, Nakamura E. Chem. Lett. 2014; 43: 676

For silicon-containing heterocyclic compounds, see:

45a Ilies L, Tsuji H, Sato Y, Nakamura E. J. Am. Chem. Soc. 2008; 130: 4240
45b Ilies L, Tsuji H, Nakamura E. Org. Lett. 2009; 11: 3966
45c Ilies L, Sato Y, Mitsui C, Tsuji H, Nakamura E. Chem. Asian J. 2010; 5: 1376

For polysubstituted hydrocarbons, see:

46a Tsuji H, Ueda Y, Ilies L, Nakamura E. J. Am. Chem. Soc. 2010; 132: 11854
46b Ueda Y, Tsuji H, Tanaka H, Nakamura E. Chem. Asian J. 2014; 9: 1623 ; see also refs. 5 (i) and 5 (j)

For carbocyclic compounds, see:

47a Zhu X, Mitsui C, Tsuji H, Nakamura E. J. Am. Chem. Soc. 2009; 131: 13596
47b Zhu X, Tsuji H, Nakabayashi K, Ohkoshi S.-i, Nakamura E. J. Am. Chem. Soc. 2011; 133: 16342
47c Zhu X, Tsuji H, López-Navarrete JT, Casado J, Nakamura E. J. Am. Chem. Soc. 2012; 134: 19254
47d Zhu X, Tsuji H, Yella A, Chauvin A.-S, Grätzel M, Nakamura E. Chem. Commun. 2013; 49: 582
47e Tsuji H, Ota Y, Furukawa S, Mitsui C, Sato Y, Nakamura E. Asian J. Org. Chem. 2012; 1: 34
47f Sukegawa J, Tsuji H, Nakamura E. Chem. Lett. 2014; 43: 699

48 Organic Field-Effect Transistors . Bao Z, Locklin J. CRC Press; Boca Raton: 2007

49a Organic Light-Emitting Devices: Synthesis, Properties and Applications. Müllen K, Scherf U. Wiley-VCH; Weinheim: 2006
49b Organic Light-Emitting Devices: A Survey . Shinar J. Springer; New York: 2004
49c Li Z, Meng H. Organic Light-Emitting Materials and Devices . CRC Press; Boca Raton: 2007

For furan-containing functional materials, see:

50a Shukla R, Wadumethrige SH, Lindeman SV, Rathore R. Org. Lett. 2008; 10: 3587
50b Hayashi N, Saito Y, Higuchi H, Suzuki K. J. Phys. Chem. A 2009; 113: 5342
50c Caruso U, Panunzi B, Roviello GN, Roviello G, Tingoli M, Tuzi A. C. R. Chim. 2009; 12: 622
50d Li H, Jiang P, Yi C, Li C, Liu S.-X, Tan S, Zhao B, Braun J, Meier W, Wandlowski T, Decurtins S. Macromolecules 2010; 43: 8058
50e Santos-Pérez J, Crespo-Hernández CE, Reichardt C, Cabrera CR, Feliciano-Ramos I, Arroyo-Ramírez L, Meador MA. J. Phys. Chem. A 2011; 115: 4157
50f Xiao J, Yang B, Wong JI, Liu Y, Wei F, Tan KJ, Teng X, Wu Y, Huang L, Kloc C, Boey F, Ma J, Zhang H, Yang HY, Zhang Q. Org. Lett. 2011; 13: 3004
50g Bijleveld JC, Karsten BP, Mathijssen SG. J, Wienk MM, de Leeuw DM, Janssen RA. J. J. Mater. Chem. 2011; 21: 1600
50h Niimi K, Mori H, Miyazaki E, Osaka I, Kakizoe H, Takimiya K, Adachi C. Chem. Commun. 2012; 48: 5892
50i Kobilka BM, Dubrovskiy AV, Ewan MD, Tomlinson AL, Larock RC, Chaudhary S, Jeffries-El M. Chem. Commun. 2012; 48: 8919
50j Li H, Tang P, Zhao Y, Liu S.-X, Aeschi Y, Deng L, Braun J, Zhao B, Liu Y, Tan S, Meier W, Decurtins S. J. Polym. Sci., Part A: Polym. Chem. 2012; 50: 2935
50k Mitsui C, Okamoto T, Matsui H, Yamagishi M, Matsushita T, Soeda J, Miwa K, Sato H, Yamano A, Uemura T, Takeya J. Chem. Mater. 2013; 25: 3952
50l Nakahara K, Mitsui C, Okamoto T, Yamagishi M, Miwa K, Sato H, Yamano A, Uemura T, Takeya J. Chem. Lett. 2013; 42: 654
50m Li H, Ding J, Chen S, Beyer C, Liu S.-X, Wagenknecht H.-A, Hauser A, Decurtins S. Chem. Eur. J. 2013; 19: 6459
50n Li S, Yuan J, Deng P, Ma W, Zhang Q. Sol. Energy Mater. Sol. Cells 2013; 118: 22
50o Bosiak MJ, Rakowiecki M, Orlowska KJ, Kedziera D, Adams J. Dyes Pigm. 2013; 99: 803
50p Gidron O, Dadvand A, Sun EW.-H, Chung I, Shimon LJ. W, Bendikov M, Perepichka DF. J. Mater. Chem. C 2013; 1: 4358
50q Mallet C, Didane Y, Watanabe T, Yoshimoto N, Allain M, Videlot-Ackermann C, Frère P. ChemPlusChem 2013; 78: 459
50r Shi S, Xie X, Gao C, Shi K, Chen S, Yu G, Guo L, Li X, Wang H. Macromolecules 2014; 47: 616
50s Moussalem C, Segut O, Gohier F, Allain M, Frére P. ACS Sustainable Chem. Eng. 2014; 2: 1043
50t Huang W, Yang B, Sun J, Liu B, Yang J, Zou Y, Xiong J, Zhou C, Gao Y. Org. Electron. 2014; 15: 1050
50u Nakahara K, Mitsui C, Okamoto T, Yamagishi M, Matsui H, Ueno T, Tanaka Y, Yano M, Matsushita T, Soeda J, Hirose Y, Sato H, Yamano A, Takeya J. Chem. Commun. 2014; 50: 5342 ; see also Ref. 10 (i)

For recent examples of heterocyclic compounds including oxygen and other heteroatoms, see:

51a Washington MP, Gudimetla VB, Laughlin FL, Deligonul N, He S, Payton JL, Simpson MC, Protasiewicz JD. J. Am. Chem. Soc. 2010; 132: 4566
51b Chen H, Delaunay W, Li J, Wang Z, Bouit P.-A, Tondelier D, Geffroy B, Mathey F, Duan Z, Réau R, Hissler M. Org. Lett. 2013; 15: 330
51c Aeschi Y, Li H, Cao Z, Chen S, Amacher A, Bieri N, Özen B, Hauser J, Decurtins S, Tan S, Liu S.-X. Org. Lett. 2013; 15: 5586

For recent examples of furan compounds, see:

52a Chou C.-M, Chen C.-H, Lin C.-L, Yang K.-W, Lim T.-S, Luh T.-Y. Tetrahedron 2009; 65: 9749
52b Woo CH, Beaujuge PM, Holcombe TW, Lee OP, Fréchet JM. J. J. Am. Chem. Soc. 2010; 132: 15547
52c Gidron O, Diskin-Posner Y, Bendikov M. J. Am. Chem. Soc. 2010; 132: 2148
52d Mohakud S, Woo CH, Alex AP, Pati SK. J. Phys. Chem. C 2010; 114: 20436
52e Gidron O, Dadvand A, Sheynin Y, Bendikov M, Perepichka DF. Chem. Commun. 2011; 47: 1976
52f Yuan J, Huang X, Zhang F, Lu J, Zhai Z, Di C, Jiang Z, Ma W. J. Mater. Chem. 2012; 22: 22734
52g Mitsudo K, Harada J, Tanaka Y, Mandai H, Nishioka C, Tanaka H, Wakamiya A, Murata Y, Suga S. J. Org. Chem. 2013; 78: 2763
52h Ledwon P, Lapkowski M, Licha T, Frydel J, Idzik KR. Synth. Met. 2014; 191: 74
52i Nakanishi K, Sasamori T, Kuramochi K, Tokitoh N, Kawabata T, Tsubaki K. J. Org. Chem. 2014; 79: 2625