Asymmetric Formal Synthesis of Cortistatins via a Gold-Catalyzed Semi-Pinacol Rearrangement Strategy
- Corresponding author: Fu Junkai, fujk109@nenu.edu.cn Gong Jianxian, gongjx@pkusz.edu.cn Yang Zhen, zyang@pku.edu.cn
Citation: Gu Yueqing, Yuan Hao, Fu Junkai, Gong Jianxian, Yang Zhen. Asymmetric Formal Synthesis of Cortistatins via a Gold-Catalyzed Semi-Pinacol Rearrangement Strategy[J]. Acta Chimica Sinica, ;2017, 75(8): 798-807. doi: 10.6023/A17040190
Aoki, S.; Watanabe, Y.; Sanagawa, M.; Setiawan, A.; Kotoku, N.; Kobayashi, M. J. Am. Chem. Soc. 2006, 128, 3148.
doi: 10.1021/ja057404h
(a) Aoki, S.; Watanabe, Y.; Tanabe, D.; Arai, M.; Suna, H.; Miyamoto, K.; Tsujibo, H.; Tsujikawa, K.; Yamamoto, H.; Kobayashi, M. Bioorg. Med.Chem. 2007, 15, 6758. (b) Watanabe, Y.; Aoki, S.; Tanabe, D.; Setiawan, A.; Kobayashi, M. Tetrahedron 2007, 63, 4074. (c) Aoki, S.; Watanabe, Y.; Tanabe, D.; Setiawan, A.; Arai, M.; Kobayashi, M. Tetrahedron Lett. 2007, 48, 4485.
For reviews on the synthesis of the cortistatins, see: (a) Nising, C. F.; Brase, S. Angew. Chem. Int. Ed. 2008, 47, 9389. Angew. Chem. 2008, 120, 9529. (b) Narayan, A. R. H.; Simmons, E. M.; Sarpong, R. Eur. J. Org. Chem.2010, 3553. (c) Chen, D. Y. K.; Tseng, C. C Org. Biomol. Chem.2010, 8, 2900.
(a) Shenvi, R. A.; Guerrero, C. A.; Shi, J.; Li, C. C.; Baran, P. S.J. Am. Chem. Soc. 2008, 130, 7241. (b) Shi, J.; Manolikakes, G.; Yeh, C. H.; Guerrero, C. A.; Shenvi, R. A.; Shigehisa, H.; Baran, P. S. J. Am. Chem. Soc. 2011, 133, 8014. (c) Nicolaou, K. C.; Sun, Y. P.; Peng, X. S.; Polet, D.; Chen, D. Y. Angew.Chem. Int. Ed. 2008, 47, 7310. Angew.Chem. 2008, 120, 7420. (d) Nicolaou, K. C.; Peng, X. S.; Sun, Y. P.; Polet, D.; Zou, B.; Lim, C. S. Chen, D. Y. J. Am. Chem.Soc. 2009, 131, 10587. (e) Lee, H. M.; Nieto-Oberhuber, C.; Shair, M. D. J. Am. Chem. Soc. 2008, 130, 16864. (f) Flyer, A. N.; Si, C.; Myers, A. G. Nat. Chem. 2010, 2, 886. (g) Yamashita, S.; Iso, K.; Kitajima, K.; Himuro, M.; Hirama, M.J. Org. Chem. 2011, 76, 2408. (h) Nilson, M. G.; Funk, R. L. J. Am. Chem. Soc. 2011, 133, 12451.
(a) Yamashita, S.; Iso, K.; Hirama, M. Org. Lett. 2008, 10, 3413. (b) Yamashita, S.; Kitajima, K.; Iso, K.; Hirama, M. Tetrahedron Lett. 2009, 50, 3277. (c) Simmons, E. M.; Hardin-Narayan, A. R.; Guo, X.; Sarpong, R. Tetrahedron 2010, 66, 4696. (d) Fang, L.; Chen, Y.; Huang, J.; Liu, L.; Quan, J.; Li, C. C.; Yang, Z. J. Org.Chem. 2011, 76, 2479. (e) Kuang, L. P.; Liu, L. L.; Chiu, P.Chem. Eur. J. 2015, 21, 14287.
(a) Dai, M.; Danishefsky, S. J. Tetrahedron Lett. 2008, 49, 6610. (b) Dai, M.; Wang, Z.; Danishefsky, S. J. Tetrahedron Lett.2008, 49, 6613. (c) Kurti, L.; Czako, B.; Corey, E. J. Org.Lett. 2008, 10, 5247. (d) Simmons, E. M.; Hardin, A. R.; Guo, X.; Sarpong, R. Angew. Chem. Int. Ed. 2008, 47, 6650. Angew. Chem. 2008, 120, 6752. (e) Kotoku, N.; Sumii, Y.; Hayashi, T.; Kobayashi, M. Tetrahedron Lett. 2008, 49, 7078. (f) Craft, D. T.; Gung, B. W. Tetrahedron Lett. 2008, 49, 5931. (g) Magnus, P.; Littich, R. Org. Lett. 2009, 11, 3938. (h) Yu, F.; Li, G.; Gao, P.; Gong, H.; Liu, Y.; Wu, Y.; Cheng, B.; Zhai, H.Org. Lett. 2010, 12, 5135. (i) Frie, J. L.; Jeffrey, C. S.; Sorensen, E. J. Org. Lett. 2009, 11, 5394. (j) Baumgartner, C.; Ma, S.; Liu, Q.; Stoltz, B. M. Org. Biomol. Chem.2010, 8, 2915. (k) Liu, L. L.; Chiu, P. Chem. Commun.2011, 47, 3416. (l) Kotoku, N.; Sumii, Y.; Kobayashi, M. Org.Lett. 2011, 13, 3514. (m) Wang, Z.; Dai, M. J.; Park, P. K.; Danishefsky, S. J. Tetrahedron 2011, 67, 10249. (n) Aquino, C.; Greszler, S. N.; Micalizio, G. C. Org. Lett. 2016, 18, 2624.
Fu, J.; Gu, Y.; Yuan, H.; Luo, T.; Li, S.; Lan, Y.; Gong, J.; Yang, Z. Nat. Commun. 2015, 6, 8617.
For selected reviews, see: (a) Hashmi, A. S. K. Chem. Rev.2007, 107, 3180. (b) Friend, C. M.; Hashmi, A. S. K. Acc. Chem.Res. 2014, 47, 729. (c) Zhang, L. Acc. Chem.Res. 2014, 47, 877. (d) Wang, Y. M.; Lackner, A. D.; Toste, F. D. Acc. Chem. Res. 2014, 47, 889. (e) Dorel, R.; Echavarren, A. M. Chem. Rev. 2015, 115, 9028. (f) Dorel, R.; Echavarren, A. M. J. Org. Chem. 2015, 80, 7321. (g) Hopkinson, M. N.; Tlahuext-Aca, A.; Glorius, F. Acc. Chem.Res. 2016, 49, 2261.
(a) Shi, H.; Fang, L.; Tan, C.; Shi, L.; Zhang, W.; Li, C. C.; Luo, T.; Yang, Z. J. Am. Chem. Soc. 2011, 133, 14944. (b) Shan, Z.; Liu, J.; Xu, L.; Tang, Y.; Chen, J.; Yang, Z. Org. Lett. 2012, 14, 3712. (c) Yue, G.; Zhang, Y.; Fang, L.; Li, C.; Luo, T.; Yang, Z. Angew. Chem. Int. Ed. 2014, 53, 1837. Angew. Chem. 2014, 126, 1868. (d) Shi, H.; Tan, C.; Zhang, W.; Zhang, Z.; Long, R.; Luo, T.; Yang, Z. Org. Lett. 2015, 17, 2342.
For selected examples, see: (a) Antoniotti, S.; Genin, E.; Michelet, V.; Genêt, J. P. J. Am. Chem. Soc. 2005, 127, 9976. (b) Hashmi, A. S. K.; Bührle, M.; Wçlfle, M.; Rudolph, M.; Wieteck, M.; Rominger, F.; Frey, W. Chem. Eur. J. 2010, 16, 9846. (c) Bihelovic. F.; Saicic, R. N. Angew. Chem. Int.Ed. 2012, 51, 5687. Angew. Chem. 2012, 124, 5785. (d) Noey, E. L.; Luo, Y.; Zhang, L.; Houk, K. N. J. Am. Chem.Soc. 2012, 134, 1078. (e) Zeng, X. Chem. Rev.2013, 113, 6864. (f) Li, D. Y.; Chen, H. J.; Liu, P. N. Angew.Chem. Int. Ed. 2016, 55, 373. Angew. Chem.2016, 128, 381.
(a) Barluenga, J.; Diéguez, A.; Fernández, A.; Rodríguez, F.; Fañanás, F. J. Angew. Chem. Int. Ed. 2006, 45, 2091. Angew. Chem. 2006, 118, 2145. (b) Barluenga, J.; Fernández, A.; Diéguez, A.; Rodríguez, F.; Fañanás, F. J. Chem. Eur.J. 2009, 15, 11660. (c) Krauter, C. M.; Hashmi, A. S. K.; Pernpointner, M. ChemCatChem 2010, 2, 1226. (d) Nagaraju, C.; Prasad, K. R. Angew. Chem. Int. Ed. 2014, 53, 10997;Angew. Chem. 2014, 126, 11177.
(a) Kirsch, S. F.; Binder, J. T.; Liébert, C.; Menz, H. Angew. Chem. Int. Ed.2006, 45, 5878. Angew. Chem. 2006, 118, 6010. (b) Crone, B.; Kirsch, S. F. Chem. Eur. J. 2008, 14, 3514. (c) Song, Z. L.; Fan, C. A.; Tu, Y. Q. Chem. Rev. 2011, 111, 7523. (d) Zhang, X. M.; Tu, Y. Q.; Zhang, F. M.; Chen, Z. H.; Wang, S. H. Chem. Soc.Rev. 2017, 46, 2272.
Gu, Y.; Zhang, P.; Fu, J.; Liu, S.; Lan, Y.; Gong, J.; Yang, Z. Adv. Synth. Catal. 2016, 358, 1392.
doi: 10.1002/adsc.201600218
(a) Morrill, C.; Funk, T. W.; Grubbs, R. H. Tetrahedron Lett.2004, 45, 7733. (b) Hemelaere, R.; Carreaux, F.; Carboni, B. J.Org. Chem. 2013, 78, 6786.
Keck, G. E.; Yates, J. B. J. Am. Chem. Soc. 1982, 104, 5829.
doi: 10.1021/ja00385a066
Kotoku, N.; Sumii, Y.; Hayashi, T.; Kobayashi, M. Heterocycles 2011, 83, 1535.
doi: 10.3987/COM-11-12195
The X-ray crystallography data for compound 53, see SI of ref. 7.
Marḱo, I. E.; Ates, A.; Gautier, A.; Leroy, B.; Plancher, J. M.; Quesnel, Y.; Vanherck, J. C. Angew. Chem. Int. Ed. 1999, 38, 3207. Angew. Chem. 1999, 111, 3411.
Ghosh, N.; Nayak, S.; Prabagar, B.; Sahoo, A. K. J. Org. Chem. 2014, 79, 2453
doi: 10.1021/jo4027319
Tan, D. S.; Dudley, G. B.; Danishefsky, S. Angew. Chem.Int. Ed. 2002, 41, 2185. Angew. Chem.2002, 114, 2289..
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Reagents and Conditions: a) Ethylene glycol (15.0 equiv.), PTSA (0.1 equiv.), Benzene (0.1 mol•L-1), refulx, 12 h, 96%; b) DIBAL-H (1.3 equiv.), DCM (0.1 mol•L-1), -78 ℃, 2 h, 80%; c) BrPPh3CH3 (4.0 equiv.), t-BuOK (4.0 equiv.), THF (0.2 mol•L-1), 0 ℃, 12 h, 90%; d) 4, 4, 5, 5-tetramethyl-2-(prop-1-en-2-yl)-1, 3, 2-dioxaboroane (8.0 equiv.), Grubbs 2nd catalyst (0.2 equiv.), DCM (0.05 mol•L-1), 50 ℃, 6 h; e) NaBO3•4H2O (6.0 equiv.), THF/H2O (V/V, 1:1, 0.05 mol•L-1), r.t., 0.5 h, 65% for two steps; f) PTSA (0.4 equiv.), THF/H2O (V/V, 1:1, 0.04 mol•L-1), 60 ℃, 12 h, 80%; g) MeONa (4.0 equiv.), MeOH (0.04 mol•L-1), r.t., 24 h, 90%.
Reagents and Conditions: a) Ph3PAuCl (0.025 equiv.), AgNTf2 (0.025 equiv.), DCM (0.2 mol•L-1), r.t., 2 h, 75%; b) allyltributyltin (3.0 equiv.), AIBN (0.5 equiv.), toluene (0.05 mol•L-1), 80 ℃, 7 h; c) PdCl2 (0.5 equiv.), CuCl (2.0 equiv.), O2 (balloon pressure), DMF/H2O (V/V, 7:1, 0.05 mol•L-1), r.t., 12 h, 70% for two steps. d) MeONa (4.0 equiv.), MeOH (0.04 mol•L-1), r.t., 24 h, 90%.
Reagents and Conditions: a) NaH (1.05 equiv.), 2-(2-bromoethyl)-2-methyl-1, 3-dioxolane (1.1 equiv.), DMSO (1.0 mol•L-1), r.t., 15 h, 50%; b) TBSOTf (1.2 equiv.), 2, 6-lutidine (2 equiv.), CH2Cl2 (0.3 mol•L-1), 0 ℃, 2 h; c) H2 (balloon pressure), Pd/C (0.08 equiv.), EtOAc (0.3 mol•L-1), r.t., 12 h; d) m-CPBA (1.1 equiv.), NaHCO3 (10 equiv.), toluene (0.6 mol•L-1), -10 ℃, 30 min, then HF (10 equiv.), THF/toluene (V/V, 1:1, 0.4 mol•L-1), 0 ℃, 30 min (5%~30% over three steps); d') NMO (2.0 equiv.), OsO4 (0.2 equiv.), acetone/water (V/V, 8:1, 0.1 mol•L-1), 50 ℃, 18 h (74% over three steps); e) MEMCl (2.0 equiv.), i-Pr2NEt (4.0 equiv.), 1, 2-dichloroethane (0.2 mol•L-1), 80 ℃, 18 h, 92%; f) PPTS (0.1 equiv.), acetone/water (V/V, 4:1, 0.2 mol•L-1), 60 ℃, 4 h; g) NaOMe (5.0 equiv.), MeOH (0.2 mol•L-1), 70 ℃, 1 h (62% over two steps).
Reagents and Conditions: a) pyridine (6.0 equiv.), SOCl2 (3.0 equiv.), DCM (0.05 mol•L-1), -10 ℃, 0.5 h, 74%; b) n-BuLi (1.5 equiv.), ethyl propiolate (1.5 equiv.), THF (0.03 mol•L-1), -78 ℃, 3 h, 50%; c) Ph3PAuCl (0.025 equiv.), AgNTf2 (0.025 equiv.), DCM (0.2 mol•L-1), r.t., 2 h, 25% for 36, 30% for 37.
Reagents and Conditions: a) NaBH4 (1.0 equiv.), EtOH (0.05 mol•L-1), -78 ℃, 3 h, 85%; b) palladium on carbon (0.1 equiv.), H2 (6.0 MPa), MeOH (0.3 mol•L-1), r.t., 18 h, 20%; c) DMP (1.1 equiv.), NaHCO3 (1.1 equiv.), DCM (0.01 mol•L-1), r.t., 2 h, 75%; d) ethynylmagnesium chloride (2.0 equiv.), THF (0.01 mol•L-1), 0 ℃ to r.t., 3 h, 90%, dr=3:1.
Reagents and Conditions: a) triethylamine (6.0 equiv.), TMSOTf (3.0 equiv.), DCM (0.03 mol•L-1), 0 ℃ to r.t., 3 h, then PPTS (0.2 equiv.), DCM (0.03 mol•L-1), r.t., 2 h, 78%; b) ethynylmagnesium choride (2.0 equiv.), THF (0.01 mol•L-1), 0 ℃ to r.t., 3 h, 85%, dr=3:1; c) Ph3PAuCl (0.025 equiv.), AgNTf2 (0.025 equiv.), DCM (0.2 mol•L-1), r.t. or 70 ℃, 2 h.
Reagents and Conditions: a) NaBH4 (2.0 equiv.), EtOH (0.1 mol•L-1), -78 ℃, 3 h, dr=1:1; b) TEA (10.0 equiv.), Ac2O (5.0 equiv.), DMAP (0.1 equiv.), DCM (0.1 mol•L-1), 40 ℃, 16 h, 72% for two steps; c) NaH (5.0 equiv.), MeI (10.0 equiv.), DMF (0.1 mol•L-1), 0 ℃ to r.t., 4 h; d) K2CO3 (1.5 equiv.), MeOH (0.1 mol•L-1), 40 ℃, 12 h; e) DMP (2.0 equiv.), DCM (0.1 mol•L-1), 0 ℃ to r.t., 2 h, 55% for three steps; f) ethynylmagnesium chloride (3.0 equiv.), THF (0.5 mol•L-1), 0 ℃ to r.t., 4 h, 95%, dr=3.8:1; g) Ph3PAuCl (0.025 equiv.), AgNTf2 (0.025 equiv.), DCM (0.02 mol•L-1), r.t., 1 h.
Reagents and Conditions: a) 2, 2-dimethylpropane-1, 3-diol (10.0 equiv.), PPTS (0.1 equiv.), benzene (0.1 mol•L-1), 50 ℃, 4 h, 80%; b) KH (4.0 equiv.), MeI (8.0 equiv.), 0 ℃ to r.t., 92%; c) CAN (0.05 equiv.), borate buffer (pH=8.0), 60 ℃, 5 h, 55%; d) ethynylmagnesium chloride (3.0 equiv.), THF (0.5 mol•L-1), 0 ℃ to r.t., 4 h, 95%, dr=3.8:1.
Reagents and Conditions: a) NBS (1.3 equiv.), AgNO3 (0.05 equiv.), acetone (0.08 mol•L-1), r.t., 0.5 h, 90%; b) Ph3PAuCl (0.025 equiv.), AgNTf2 (0.025 equiv.), DCM (0.02 mol•L-1), r.t., 1 h, 81%; c) allyltributyltin (10.0 equiv.), AIBN (0.5 equiv.), benzne (0.05 mol•L-1), 80 ℃, 18 h, 78%; d) PdCl2 (0.2 equiv.), CuCl (1.5 equiv.), O2 (balloon pressure), DMF/H2O (V/V, 7:1, 0.1 mol•L-1), r.t., 12 h, 90%; e) NaOMe (2.0 equiv.), MeOH (0.03 mol•L-1), r.t., 10 h, 70%; f) triethylamine (10.0 equiv.), trimethylsilyl trifluoromethanesulfonate (6.0 equiv.), N-bromosuccinimide (3.0 equiv.), THF (0.02 mol•L-1), 0 ℃, 1 h, 80%.