Stable diaqua palladium(II) complexes of BINAP and Tol-BINAP as highly efficient catalysts for asymmetric aldol reactions

Synlett

Volumn , Issue SPEC. ISS., 1997, Pages 463-466

  Sodeoka, Mikiko ^a,b   Tokunoh, Ryosuke ^a   Miyazaki, Futoshi ^a   Hagiwara, Emiko ^b   Shibasaki, Masakatsu ^a  

^a UNIVERSITY OF TOKYO   (Japan)

^b SAGAMI CHEMICAL RESEARCH CENTER   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0003914496     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1997-6145     Document Type: Article

References (22)

1. For aldol reactions via transition metal enolate: (a) Sato, S.; Matsuda, I.; Izumi, Y. Tetrahedron Lett. 1986, 27, 5517.
2. (b) Sato, S.; Matsuda, I.; Izumi, Y. J. Organomet. Chem. 1988, 352, 223.
3. (c) Slough, G. A.; Bergman, R. G.; Heathcock, C. H. J. Am. Chem. Soc. 1989, 111, 938.
4. (d) Soga, T.; Takenoshita, H.; Yamada, M.; Mukaiyama, T. Bull. Chem. Soc. Jpn. 1990, 63, 3122.
5. (e) Nokami, J.; Mandai, T.; Watanabe, H.; Ohyama, H.; Tsuji, J. J. Am. Chem. Soc. 1989, 111, 4126.
6. Ru catalysts: (f) Naota, T.; Taki, H.; Mizuno, M.; Murahashi, S. J. Am. Chem. Soc. 1989, 111, 5954.
7. (g) Reetz, M. T.; Vougioukas, A. E. Tetrahedron Lett., 1987, 28, 793.
8. (h) Roos, G. H. P.; Haines, R. J.; Raab, C. E. Synth. Commun. 1993, 23, 1251. See also the references cited in ref.(2).
9. Sodeoka, M.; Ohrai, K.; Shibasaki, M. J. Org. Chem. 1995, 60, 2648.
10. Ozawa, F.; Kubo, A.; Matsumoto, Y.; Hayashi, T.; Nishioka, E.; Yanagi, K.; Moriguchi, K. Organometallics, 1993, 12, 4188.
11. 3 Since these two complexes were found to show basically the same reactivity and asymmetric induction, we used both complexes for this research.
12. 2 (5 mol %) and (R)-Tol-BINAP (5 mol %) in wet DMF in the presence of 4A molecular sieves also effectively catalyzed the condensation of 2 with 3 to give 4 (98%, 69% ee) and 5 (2%, 64% ee).
13. 2O: C, 57.49; H, 4.52, Found: C, 57.37; H, 4.47.
14. 6
15. 2; however, we have isolated only the diaqua complexes with these bulky bidentate ligands. See: Bushnell, G. W.; Dixon, K. R.; Hunter, R. G.; McFarland, J. J. Can. J. Chem. 1972, 50, 3694.
16. 2O: 4%, 67% ee).
17. The chemical and optical yields of the aldol products from the reactions using 5 mol % of the catalyst prepared in situ by our original procedure were as follows: 11, 80% (73% ee), 13, syn, 43% (72% ee), anti, 15% (18% ee), 15, 86% (73% ee). For determination of the ee of 11, 13, and 15, see ref. (2).
18. The concentration of reagents was important for the reactivity and asymmetric induction when TMU was used as the solvent. Reaction at ca. 0.67 M of 2 in TMU was slower than that at 0.1 M, and the optical yield of the product decreased from 84% ee to 76% ee. No dependence of optical yield on concentration was observed for the reaction in DMF.
19. iPrOH, 9:1).
20. The reaction in TMU using 1 mol % of 9a gave the less satisfactory result.
21. Stang et al. have reported a similar diaqua palladium (II) complex of bis(diphenylphosphino)propane and mono aqua palladium(II) complex of BINAP. See, (a) Stang, P. J.; Cao, D. H.; Poulter, G. T.; Arif, A. M. Organometallics 1995, 14, 1110.
22. b) Stang, P. J.; Olenyuk, B.; Arif, A. M. Organometallics 1995, 14, 5281, and references cited therein for other examples of aqua complexes.