Hydrogenation of hindered ketones catalyzed by a silica-supported compact phosphine-Rh system

Organic Letters

Volumn 10, Issue 20, 2008, Pages 4697-4700

  Kawamorita, Soichiro ^a   Hamasaka, Go ^a   Ohmiya, Hirohisa ^a   Hara, Kenji ^a   Fukuoka, Atsushi ^a   Sawamura, Masaya ^a  

^a HOKKAIDO UNIVERSITY   (Japan)

Author keywords

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Indexed keywords

EID: 61349098845     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol801996r     Document Type: Article

References (15)

1. Klomp, D.; Hanefeld, U.; Peters, J. A. In Handbook of Homogeneous Hydrogenation; de Vries, J. G.; Elsevier, C. J., Ed.; Wiley-VCH: Winheim, Germany, 2007; Vol. 2, pp 585-630.
2. (a) Blum, Y.; Czarkle, D.; Rahamim, Y.; Shvo, Y. Organometallics 1985, 4, 1459-1461. For review on homogeneous hydrogenation of carbonyl compounds, see:
3. (b) Clarke, M. L.; Roff, G. J. In Handbook of Homogeneous Hydrogenation; de Vries, J. G.; Elsevier, C. J., Ed.; Wiley-VCH: Winheim, Germany, 2007; Vol. 1, pp 413-454.
4. Diisopropyl ketone (3a) could not be reduced with Raney nickel or with nickel and some promoters, but was finally reduced with an equal weight of catalyst promoted with chloroplatinic acid and sodium hydroxide. See: (a) Blance, R. B.; Gibson, D. T. J. Chem. Soc. 1954, 2487-2489.
5. See also: (b) Freiferder, M. In Catalytic Hydrogenation in Organic Synthesis. Procedures and Commentary; Wiley: New York, 1978; Chapter 9, pp 78-89. Hydrogenation of 3a with Shvo's Ru catalyst required a high hydrogenation pressure (34 atm) and a high reaction temperature (145 °C, 3 h) to gain the TON of 1760 (ref 2a).
6. For the vapor phase transfer hydrogenation using: isopropyl alcohol as a hydrogen donor over a calcinated Mg-Al hydrotalcites catalyst at 200 °C, see: Jyothi, T. M.; Raja, T.; Rao, B. S. J. Mol. Catal., A 2001, 168, 187-191.
7. SMAP: silicon-constrained monodentate trialkylphosphine. See: (a) Ochida, A.; Hara, K.; Ito, H.; Sawamura, M. Org. Lett. 2003, 5, 2671-2674.
8. (b) Ochida, A.; Ito, S.; Miyahara, T.; Ito, H.; Sawamura, M. Chem. Lett. 2006, 35, 294-295.
9. (c) Ochida, A.; Hamasaka, G.; Yamauchi, Y.; Kawamorita, S.; Oshima, N.; Hara, K.; Ohmiya, H.; Sawamura, Organometallics, in press.
10. (a) Hamasaka, G.; Ochida, A.; Hara, K.; Sawamura, M. Angew. Chem., Int. Ed. 2007, 46, 5381-5383.
11. (b) Hamasaka, G.; Kawamorita, S.; Ochida, A.; Akiyama, R.; Hara, K.; Fukuoka, A.; Asakura, K.; Chun, W. J.; Ohmiya, H.; Sawamura, M. Submitted for publication.
12. For a related study with a self-assembled monolayer of SMAP on gold surface, see: Hara, K.; Akiyama, R.; Takakusagi, S.; Uosaki, K.; Yoshino, T.; Kagi, H.; Sawamura, M. Angew. Chem., Int. Ed. 2008, 47, 5627-5630.
13. Silica-SMAP (1) was prepared with CARiACT Q-10 silica gel (Fuji Silysia Chemical Ltd.). Rh complex 2a (yellow powder) was prepared according to the reported procedure for a preparation of the corresponding chloro complex (2b) (see ref 6).
14. 3N is unclear.
15. Reusability of the silica-SMAP-Rh system has not been examined in the present study because of the expected difficulty in handling highly active catalytic species under the hydrogenation conditions in the laboratory experiments. Instead, the silica-SMAP-Rh catalyst system that was generated from chloro complex 2b displayed excellent reusability in the hydrosilylation of ketones (see, ref 6).