Tishchenko Reaction Using an Iridium-Ligand Bifunctional Catalyst

Abstract

Tishchenko reaction of aldehydes in the presence of an amino alcohol-based Ir bifunctional catalyst was developed. The reaction proceeds with 1 mol% of the catalyst and 20-30 mol% of K₂CO₃ in acetonitrile at room temperature to give the corresponding dimeric esters in good yield.

Key words

aldehydes - esters - hydrogen transfer - iridium catalyst - Tishchenko reaction

References

• 1a Tischtschenko W. Chem. Zentralbl.  1906,  77:  1309 
• 1b Larock RC. Comprehensive Organic Transformations   VCH Publishers, Inc.; New York: 1989.  p.840 
• 1c For a recent review: Törmäkangas OP. Koskinen AMP. Recent Res. Dev. Org. Chem.  2001,  5:  225 
• 2 For recent examples of Tishchenko-related reactions, see: Gnanadesikan V. Horiuchi Y. Ohshima T. Shibasaki M. J. Am. Chem. Soc.  2004,  126:  7782 ; and references cited therein
• 3 Stapp PR. J. Org. Chem.  1973,  38:  1433 
• 4 Yamashita M. Watanabe Y. Mitsudo T.-a. Takegami Y. Bull. Chem. Soc. Jpn.  1976,  49:  3597 
• 5a Ito T. Horino H. Koshiro Y. Yamamoto A. Bull. Chem. Soc. Jpn.  1982,  55:  504 
• 5b Menashe N. Shvo Y. Organometallics  1991,  10:  3885 
• 6 Morita K. Nishiyama Y. Ishii Y. Organometallics  1993,  12:  3748 
• 7a Onozawa S.-y. Sakakura T. Tanaka M. Shiro M. Tetrahedron  1996,  52:  4291 
• 7b Berberich H. Roesky PW. Angew. Chem. Int. Ed.  1998,  37:  1569 
• 7c Bürgstein MR. Berberich H. Roesky PW. Chem.-Eur. J.  2001,  7:  3078 
• 8a Bernard KA. Atwood JD. Organometallics  1988,  7:  235 
• 8b Bernard KA. Atwood JD. Organometallics  1989,  8:  795 
• 9 Barrio P. Esteruelas MA. Oñate E. Organometallics  2004,  23:  1340 
• 10a Ooi T. Miura T. Takaya K. Maruoka K. Tetrahedron Lett.  1999,  40:  7695 
• 10b Simpura I. Nevalainen V. Tetrahedron  2001,  57:  9867 
• 10c Ooi T. Ohmatsu K. Sasaki K. Miura T. Maruoka K. Tetrahedron Lett.  2003,  44:  3191 
• 11a Suzuki T. Morita K. Tsuchida M. Hiroi K. Org. Lett.  2002,  4:  2361 
• 11b Suzuki T. Morita K. Matsuo Y. Hiroi K. Tetrahedron Lett.  2003,  44:  2003 
• 11c Suzuki T. Morita K. Tsuchida M. Hiroi K. J. Org. Chem.  2003,  68:  1601 
• For a related synthesis of dimeric esters using oxidative dimerization of primary alcohol, see:
• 11d Suzuki T. Matsuo T. Watanabe K. Katoh T. Synlett  2005,  in press 
• Recent examples of hydrogen transfer reaction using Cp*Ir complexes, see:
• 12a Mashima K. Abe T. Tani K. Chem. Lett.  1998,  1199 
• 12b Murata K. Ikariya T. Noyori R. J. Org. Chem.  1999,  64:  2186 
• 12c Ogo S. Makihara N. Watanabe Y. Organometallics  1999,  18:  5470 
• 12d Ogo S. Makihara N. Kaneko Y. Watanabe Y. Organometallics  2001,  20:  4903 
• 12e Fujita K. Furukawa S. Yamaguchi R. J. Organomet. Chem.  2002,  649:  289 
• 12f Fujita K. Yamamoto K. Yamaguchi R. Org. Lett.  2002,  4:  2691 
• 12g Abura T. Ogo S. Watanabe Y. Fukuzumi S. J. Am. Chem. Soc.  2003,  125:  4149 
• 12h Fujita K. Li Z. Ozeki N. Yamaguchi R. Tetrahedron Lett.  2003,  44:  2687 
• 12i Fujita K. Kitatsuji C. Furukawa S. Yamaguchi R. Tetrahedron Lett.  2004,  45:  3215 
• 12j Fujita K. Fujii T. Yamaguchi R. Org. Lett.  2004,  6:  3525 
• 12k Hanasaka F. Fujita K. Yamaguchi R. Organometallics  2004,  23:  1490 
• 15 Although the role of the K₂CO₃ is not clear at present, it might increase the nucleophilicity of the reduced alcohol 5 to the corresponding aldehyde for the formation of the hemiacetal 6. For the mechanistic study of acid- and base-catalyzed formation of the hemiacetal, see: Sorensen PE. Jencks WP. J. Am. Chem. Soc.  1987,  109:  4675 

13

Although Cs₂CO₃ also showed similar reactivity (ca. 90%), the use of other bases, such as Na₂CO₃, KHCO₃, KOAc, and Et₃N resulted in lower reactivity (<10% yield). t-BuOK afforded the aldol condensation product without forming the dimeric ester.

14

Although TONs were not optimized at the moment, they were roughly calculated to be in range between 43 and 49 for most substrates.

16

In a control experiment, no reaction took place without Ir complex (in the presence of K₂CO₃).

17

In most cases, a small amount of alcohol remained even after the aldehyde was completely consumed.