Notes and References - Asymmetric Copper-Catalyzed Alkylation of N-Heterocycles

Chapter 4: Asymmetric Copper-Catalyzed Alkylation of N-Heterocycles

4.5. Notes and References

(3S)-3-Bromo-1-phenylpyrrolidin-2-one. A suitable crystal for X-ray crystallography was grown by vapor diffusion with isopropanol and hexane.

A crystal of C10H10BrNO was selected and mounted in a nylon loop in immersion oil. All measurements were made on a Bruker APEX2 diffractometer with filtered Mo-Kα radiation at a temperature of 100 K. Using Olex2³¹, the structure was solved with the ShelXS structure solution program using Direct Methods and refined with the ShelXL refinement package³⁰ using Least Squares minimization. The absolute stereochemistry was determined on the basis of the absolute structure parameter.

Zhou, Q.-L. Chem. Rev. 2011, 111, 1713–1760. (d) Wang, C.; Xiao, J. Top. Curr.

Chem. 2013, 343, 261−282.

4. For recent reviews of asymmetric hydroaminations, see: (a) Huang, L.; Arndt, M.;

Gooßen, K.; Heydt, H.; Gooßen, L. J. Chem. Rev. 2015, 115, 2596–2697. (b) Soradova, Z.; Sebesta, R. ChemCatChem 2016, 8, 1–9. (c) Pirnot, M. T.; Wang, Y.-M.; Buchwald, S. L. Angew. Chem. Int. Ed. 2016, 55, 48–57.

5. For recent reviews of asymmetric C−H aminations, see: (a) Collet, F.; Lescot, C.; Dauban, P. Chem. Soc. Rev. 2011, 40, 1926–1936. (b) Lebel, H.; Trudel, C.; Spitz, C. Chem.

Commun. 2012, 48, 7799–7801. (c) Gephart, R. T.; Warren, T. H. Organometallics 2012, 31, 7728–7752. (d) Zheng, C.; You, S.-L. RSC Adv. 2014, 4, 6173–6214. (e) Park, Y.;

Kim, Y.; Chang, C. Chem. Rev. 2017, 117, 9247–9301.

6. For recent reviews of transition-metal catalyzed cross-couplings reactions to form Csp2−N bonds, see: (a) Surry, D. S.; Buchwald, S. L. Chem. Sci. 2010, 2, 27–50. (b) Qiao, J. X.;

Lam, P. Y. S. Synthesis 2011, 2011, 829–856. (c) Beletskaya, I. P.; Cheprakov, A. V.

Organometallics 2012, 31, 7753–7808 (d) Bariwal, J.; Eycken, E. V. der. Chem. Soc.

Rev. 2013, 42, 9283–9303. (e) Casitas, A.; Ribas, X. Chem. Sci. 2013, 4, 2301. (e) Sambiagio, C.; Marsden, S. P.; Blacker, A. J.; McGowan, P. C. Chem. Soc. Rev. 2014, 43, 3525–3550. (f) Ruiz-Castillo, P.; Buchwald, S. L. Chem. Rev. 2016, 116, 12564–

12649.

7. For early examples of reactions of unactivated alkyl electrophiles (all are primary alkyl bromides) that proceed in the presence of a substoichiometric quantity of a transition metal, see: (a) Kozuka, M.; Tsuchida, T.; Mitani, M. Tetrahedron Lett. 2005, 46, 4527−4530. (b) Tu, X.; Fu, X.; Jiang, Q.; Liu, Z.; Chen, G. Dyes Pigm. 2011, 88, 39−43.

8. For examples of transition-metal catalyzed reactions between amines and alkyl electrophiles, see: (a) Peacock, D. M.; Roos, C. B.; Hartwig, J. F. ACS Cent. Sci. 2016, 2, 647−652. (b) Liang, Y.; Zhang, X.; MacMillan, D. W. C. Nature 2018, 559, 83–88.

9. For examples of photoinduced copper-catalyzed alkylation of amines from our group, see:

(a) Creutz, S. E.; Lotito, K. J.; Fu, G. C.; Peters, J. C. Science 2012, 338, 647–651. (b)

Bissember, A. C.; Lundgren, R. J.; Creutz, S. E.; Peters, J. C.; Fu, G. C. Angew. Chem.

Int. Ed. 2013, 52, 5129–5133. (c) Do, H.-Q.; Bachman, S.; Bissember, A. C.; Peters, J.

C.; Fu, G. C. J. Am. Chem. Soc. 2014, 136, 2162–2167. (d) Zhao, W.; Wurz, R. P.; Peters, J. P.; Fu, G. C. J. Am. Chem. Soc., 2017, 139, 12153–12156. (e) Matier, C. D.; Schwaben, J.; Peters, J. C.; Fu, G. C. J. Am. Chem. Soc., 2017, 139, 17707–17710. (f) Ahn, J. M.;

Peters, J. C.; Fu, G. C. J. Am. Chem. Soc., 2017, 139, 18101–18106.

10. Kainz, Q. M.; Matier, C. D.; Bartoszewicz, A.; Zultanski, S. L.; Peters, J. C.; Fu, G. C.

Science 2016, 351, 681–684.

11. (a) Thorsett, E. D.; Harris, E. E.; Aster, S. D.; Peterson, E. R.; Snyder, J. P.; Springer, J.

P.; Hirshfield, J.; Tristram, E. W.; Patchett, A. A. J. Med. Chem. 1986, 29, 251−260. (b) Semple, J. E.; Rowley, D. C.; Brunck, T. K.; Ha-Uong, T.; Minami, N. K.; Owens, T.

D.; Tamura, S. Y.; Goldman, E. A.; Siev, D. V.; Ardecky, R. J.; Carpenter, S. H.; Ge, Y.;

Richard, B. M.; Nolan, T. G.; Håkanson, K.; Tulinsky, A.; Nutt, R. F.; Ripka, W. C. J.

Med. Chem. 1996, 39, 4531−4536. (c) Tamura, S. Y.; Goldman, E. A.; Brunck, T. K.;

Ripka, W. C.; Edward Semple, J. Bioorg. Med. Chem. Lett. 1997, 7, 331−336. (d) Bell, I. M.; Gallicchio, S. N.; Abrams, M.; Beese, L. S.; Beshore, D. C.; Bhimnathwala, H.;

Bogusky, M. J.; Buser, C. A.; Culberson, J. C.; Davide, J.; Ellis-Hutchings, M.;

Fernandes, C.; Gibbs, J. B.; Graham, S. L.; Hamilton, K. A.; Hartman, G. D.; Heimbrook, D. C.; Homnick, C. F.; Huber, H. E.; Huff, J. R.; Kassahun, K.; Koblan, K. S.; Kohl, N.

E.; Lobell, R. B.; Lynch, Joseph J.; Robinson, R.; Rodrigues, A. D.; Taylor, J. S.; Walsh, E. S.; Williams, T. M.; Zartman, C. B. J. Med. Chem. 2002, 45, 2388−2409. (e) Kemp, J. A.; Leeson, P. D. Trends Pharmacol. Sci. 1993, 14, 20−25.

12. It was found in the absence of a copper catalyst the electrophile reacts with (R)−4.1 in m- xylene at room temperature to form a 1:1 mixture of diastereomers of the corresponding phosphonium salt. A similar salt could not be detected by ³¹P NMR analysis in an unmodified reaction mixture (Table 4.1, entry 1). When the isolated phosphonium salt (mixture of diastereomers) was used in place of the electrophile in the C–N cross- coupling (without catalyst), no product formation was observed.

13. (a) Phosphine 4.1 is commercially available from Strem Chemicals. (b) For the original synthesis of 4.1 see: Zhu, S.-F.; Yang, Y.; Wang, L.-X.; Liu, B.; Zhou, Q.-L.

Org. Lett. 2005, 7, 2333−2335.

14. (a) Under the optimized conditions, 5-membered lactams containing chloride, tosylate, and mesylate leaving groups did not undergo conversion, while the one with nonaflate provided high yield but low ee. (b) 3-Iodopyrrolidin-2-ones with bulkier R groups, such as 2,6-diisopropylphenyl and 2,4,6-trimethylphenyl, afforded low yields. (c) 3-Iodo-4,4- dimethyl-1-phenylpyrrolidin-2-one and acyclic α-iodoamides gave low yields (<5%). (d) 7-Membered α-iodolactam gave predominantly the elimination product.

15. To avoid complications with the racemization of the starting material, 3-bromo-1- phenylpyrrolidin-2-one was used in these experiments.

16. (a) Terao, J.; Todo, H.; Begum, S. A.; Kuniyasu, H.; Kambe, N. Angew. Chem. Int. Ed.

2007, 46, 2086−2089. (b) Yang, C.-T.; Zhang, Z.-Q.; Liang, J.; Liu, J.-H.; Lu, X.-Y.;

Chen, H.-H.; Liu, L. J. Am. Chem. Soc. 2012, 134, 11124−11127.

17. To avoid additional complications with the kinetic resolution and the racemization of the starting material, an enantiopure matched 3-bromo-1-phenylpyrrolidin-2-one was used in these experiments. For the details of the calculation of the relative rates, see the supporting information.

18. In a catalytic competition reaction with these three differently 5-substituted 3- methylindoles a similar selectivity trend was observed. This result suggests that the selectivity in the catalytic reaction is predominantly governed by the intrinsic relative reactivities of the complexes of type 4.5, and not by the relative rates of the deprotonation of the nucleophiles or the relative stability of these complexes. Due to the heterogeneity of the reaction mixture, we have not been able to perform meaningful kinetics studies.

19. Huang, Z.; Hartwig, J. F. Angew. Chem. Int. Ed. 2012, 51, 1028 –1032.

20. Lin, X.; Chen, W.; Qiu, Z.; Guo, L.; Zhu, W.; Li, W.; Wang, Z.; Zhang, W.; Zhang, Z.;

Rong, Y.; Zhang, M.; Yu, L.; Zhong, S.; Zhao, R.; Wu, X.; Wong, J. C.; Tang, G., J.

Med. Chem. 2015, 58, 2809−2820.

21. Kamal, A.; Ramana, K. V.; Ramana, A. V.; Babu, A. H Tetrahedron: Asymmetry 2003, 14, 2587−2594.

22. Sedlák, M.; Hanusek, J.; Macháček, V.; Hejtmánková, L. J. Heterocyc. Chem. 2002, 39, 1105−1107.

23. Okawara, T.; Matsuda, T.; Furukawa, M. Chem. Pharm. Bull. 1982, 30, 1225−1233.

24. Mesitylcopper was prepared using procedure described previously in literature: Tsuda, T.; Yazawa, T.; Watanabe, K.; Fujii, T.; Saegusa, T. J. Org. Chem. 1981, 46, 192−194.

25. (R)-SITCP [(R)−4.1] and (S)-SITCP [(S)−4.1] were purchased from Strem Chemicals.

26. Cs2CO3 used in all experiments was of 99.995% purity.

27. Wu, H.-C.; Yu, J.-Q.; Spencer, J. B. Org. Lett. 2004, 6, 4675−4678.

28. Zhu, S.-F.; Yang, Y.; Wang, L.-X.; Liu, B.; Zhou, Q.-L. Org. Lett. 2005, 7, 2333−2335.

29. (a) Ingold, C. K.; Shaw, F. R. J. Chem. Soc. 1927, 2918−2926. (b) Yau, H. M.; Croft, A.

K.; Harper, J. B. Chem. Comm. 2012, 48, 8937−8939.

30. Sheldrick, G. M. Acta. Crystallogr. A. 2008, 64, 112.

31. Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. J Appl Crystallogr. 2009, 42, 339.

C h a p t e r 5

ENANTIOCONVERGENT CROSS-COUPLINGS OF ALKYL ELECTROPHILES: THE CATALYTIC ASYMMETRIC SYNTHESIS OF

ORGANOSILANES

Adapted with permission from:

Schwarzwalder, G. M.^‡; Matier, C. D.^‡; Fu, G. C. Enantioconvergent Cross-Coupling of Alkyl Electrophiles: The Catalytic Asymmetric Synthesis of Organosilanes. Angew.

Chem. Int. Ed. 2019, 58, 3571–3574. doi: 10.1002/anie.201814208

Significant progress has been described in the development of methods for the synthesis of carbon–carbon bonds through enantioconvergent substitution reactions of racemic alkyl electrophiles with carbon nucleophiles.^1–3 To date, high enantioselectivity has only been observed in cross-couplings wherein the electrophile bears either a directing group (5.I) or a p/π orbital proximal to the leaving group (5.II) (Figure 5.1).⁴

Figure 5.1. Background: Racemic electrophiles used in enantioconvergent cross-couplings.

5.I and 5.II: Prior work. 5.III: This study.

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