硕士论文答辩PPT

1、2020/7/18,1,答辩人：XXX 导师: XXX教授,光催化2-取代苯并噻唑的合成及芳烃C-H官能化研究 New Synthetic Methods for the Preparation of 2-Substituted Benzothiazoles And Photocatalytic Direct C-H Arylation,2020/7/18,2,Contents 1. Background 2. Research proposal 3. Work progress (I, II, III, IV) 4. Acknowledgment,2020/7/18,3,1.1. Backg

2、round of Photoredox Chemistry,R: generic organic substituent FG: electron-withdrawing functional group,1. Background,Nicewicz, D. A.; MacMillan, D. W. C. Science 2008, 322, 77,Hedstrand, D. M.; Kellogg, R. M. Tetrahedron Lett. 1978, 19, 1255,2020/7/18,4,Dai, C.; Narayanam, J. M. R.; Stephenson, C. R

3、. J. Nat. Chem. 2011, 3, 140,Ischay, M. A.; Anzovino, M. E.; Du, J.; Yoon, T. P. J. Am. Chem. Soc. 2008, 31, 14604,2020/7/18,5,1.2. Background of 2-Substituted Benzothiazoles,Fatty acid amide hydrolase inhibitor,Antitumor agent,Zopolrestat,2020/7/18,6,1.2.1. Main Synthetic Methods of 2-Substituted B

4、enzothiazoles,1.Bahrami, K. Khodaei, M. M. J. Org. Chem. 2008, 73, 6835 2.Yao. S.; Schafer-Hales, K. J.; Beleld, K. D. Org. Lett. 2007, 9, 5645 3.Bose, D. S.; Idrees, M. J. Org. Chem. 2006, 71, 8261 4.Joyce, L. L.; Evindar, G.; Batery, R. A. Chem. Commun. 2004, 446 5.Saha, P.; Ramana, T.; Ali, M. A.

5、; Paul, R.; Punniyamurthy,T. J. Org. Chem. 2009, 74, 8719 6.Inamoto, K.; Hasegawa, C.; Hiroya, K.; Doi, T. Org. Lett. 2008, 10, 5147 7.Joyce, L. L.; Batey, R. A. Org. Lett. 2009, 11, 2792 8.Mu, X.; Zou, J.; Tetrahedron Lett. 2005, 46, 4345,2020/7/18,7,Inamoto, K.; Hasegawa, C.; Hiroya, K.; Doi, T. O

6、rg. Lett. 2008, 10, 5147,Joyce, L. L.; Batey, R. A. Org. Lett. 2009, 11, 2792,2020/7/18,8,2. Research proposal,?,2020/7/18,9,3.Work progress,I. Aerobic Visible-Light Photoredox Radical C-H Functionalization: Catalytic Synthesis of 2-Substituted Benzothiazoles,2020/7/18,10,a: HPLC yield ; b: Isolated

7、 yield; c: Under 5% O2 balloon.; d: 0.5 equiv DBU was used.e: Reaction was carried out in dark. f: Under air; g: Under 100% O2 balloon,Table 1. Optimization of Reaction Conditions,2020/7/18,11,Table 2. Synthesis of 2-Phenylbenzothiazoles,2020/7/18,12,Table 3. Substitutions on the 2-Phenyl group,2020

8、/7/18,13,Scheme 2 The Proposed Mechanism,Photoredox under sunlight,Scheme 1. Intramolecular Kinetic Study,2020/7/18,14,II. Heterogeneous Ligand-free Pd/C Catalyzed Synthesis of 2-Substituted Benzothiazoles,2020/7/18,15,Table 1. Optimization of Reaction Conditions,2020/7/18,16,Table 2. Synthesis of 2

9、-Arylbenzothiazoles,a: Reaction conditions: substrate (1 eq.), Pd/C (2 mol%), rt, N2 atmosphere, 24 hr. b: Isolated yield; c: Pd/C (5 mol%);,17,Table 3. Synthesis of 2-Alkylbenzothiazoles,b: Isolated yield; c: Pd/C (5 mol%); d: Pd/C (10 mol%);,2020/7/18,18,III. Transition-Metal-Free Cyclization For

10、the Preparation of 2-Substituted Benzothiazoles,2020/7/18,19,Table 1. Optimization of Reaction Conditions,2020/7/18,20,Table 2. Synthesis of 2-Arylbenzothiazoles,b: isolated yield , c: reaction time is 24h, d: reaction temperature was 120 C,2020/7/18,21,Table 3. Synthesis of 2-Alkylbenzothiazoles,b:

11、 isolated yield, c: reaction temperature was 120 C,2020/7/18,22,4. Summary,1) visible-light is the reaction driving force 2) molecular oxygen is the terminal oxidant 3) C-H Functionalization,1) ligand-free 2) room temperature 3) can tolerate many functional groups,1) transition-metal-free 2) tolerat

12、e many functional groups 3) staring material readily available,IV: Visible-Light Photoredox in Homolytic Aromatic Substitution: Direct Arylation of Arenes with Aryl Halides,23,Sun, C. L.; Li, H.; Yu, D. G.; Yu, M.; Zhou, X.; Lu, X. Y.; Huang, K.; Zheng, S. F.; Li, B. J.; Shi, Z. J. Nat. Chem. 2010,

13、2, 1044,Liu, W.; Cao, H.; Zhang, H.; Chung, K. H.; He, C.; Wang, H.; Kwong, F. Y.; Lei, A. J. Am. Chem. Soc. 2010, 132, 16737,Shirakawa, E.; Itoh, K.; Higashino, T.; Hayashi, T. J. Am. Chem. Soc. 2010, 132, 15537,Liu, W.; Tian, F.; Wang, X.; Yu, H.; Bi, Y. Chem. Commun. 2013, 49, 2983,24,Nguyen, J.

14、D.; DAmato, E. M.; Narayanam, J. M. R.; Stephenson, C. R. J. Nat. Chem. 2012, 4, 854,Kim, H.; Lee, C. Angew. Chem. Int. Ed. 2012, 51, 12303,25,碘苯的还原电位: -1.59-2.24V, -1.73v(Ir4+ Ir3+*) Versus SCE,Table 1. Optimization of Reaction Conditionsa,a: reaction conditions: iodobenzene (0.5 mmol), catalyst (0

15、.5 mol%), base (3 equiv.) in benzene (3 mL), irradiated under a 14 W compact fluorescent lamp irradiation at room temperature. b: GC yield; c: freeze-thaw degassed; d: reaction was carried out in dark,26,Table 2. HAS reactions of aryl iodide with benzenea,27,Table 3HAS reactions of aryl bromide with

16、 benzenea,b: Isolated yield; c: the reaction temperature was at room temperature; d: the reaction temperature was at 35 C; e: the reaction temperature was 80 C; f: the reaction temperature was 90 C g: GC yield.,28,Table 4. HAS reactions of aryl halides with arenesa,29,Scheme 1. The Proposed Mechanis

17、m,30,2020/7/18,31,Budn, M. E.; Guastavino, J. F.; Rossi, R. A. Org. Lett. 2013, 15, 1174.,Our group,Org. Lett. 2013, 15, xxxx，DOI:10.1021/ol400946k,2020/7/18,32,Publications: 1. Aerobic Visible-Light Photoredox Radical Catalytic Synthesis of 2-Substituted Benzothiazoles Yannan Cheng, Jun Yang, Yue Q

18、u, and Pixu Li* Org. Lett. 2012,14, 98101 Visible-Light Photoredox in Homolytic Aromatic Substitution: Direct Arylation of Arenes with Aryl Halides Yannan Cheng, Xiangyong Gu, and Pixu Li* Org. Lett. 2013, 15, xxxxxxxx Manuscripts in preparation: 2. Heterogeneous Ligand-free Pd/C Catalyzed Synthesis of 2-Substituted Benzothia