Enantioselective Addition of Diethylzinc to Aldehydes Catalyzed by (1R,2R)-10-(Dialkylamino)isoborneols

Abstract

(1R,2R)-10-Dialkylaminoisoborneols, γ-amino alcohol-type ligands, were synthesized from (+)-ketopinic acid. Their catalytic ability as a chiral ligand for enantioselective addition of diethylzinc to aldehydes was evaluated. Among them, the ligand with a 9-azabicyclo[3.3.1]nonan-9-yl group as an amino moiety was the most effective and showed good enantioselectivity towards various aldehydes.

Key words

aldehydes - amino alcohols - diethylzinc - enantioselective addition - enantioselectivity

References

• 1 Oguni N. Omi T. Tetrahedron Lett.  1984,  25:  2823 
• 2a Noyori R. Angew. Chem., Int. Ed. Engl.  1991,  30:  49 
• 2b Soai K. Niwa S. Chem. Rev.  1992,  92:  833 
• 2c Pu L. Yu H.-B. Chem. Rev.  2001,  101:  757 
• 3 Kitamura M. Suga S. Kawai K. Noyori R. J. Am. Chem. Soc.  1986,  108:  6071 
• 4 Nugent WA. Chem. Commun.  1999,  1369 
• 5a Genov M. Kostova K. Dimitrov V. Tetrahedron: Asymmetry  1997,  8:  1869 
• 5b Philipova I. Dimitrov V. Simova S. Tetrahedron: Asymmetry  1999,  10:  1381 
• 5c Knollmüller M. Ferencic M. Gärtner P. Tetrahedron: Asymmetry  1999,  10:  3969 
• 5d Hanyu N. Aoki T. Mino T. Sakamoto M. Fujita T. Tetrahedron: Asymmetry  2000,  11:  2971 
• 5e Hanyu N. Aoki T. Mino T. Sakamoto M. Fujita T. Tetrahedron: Asymmetry  2000,  11:  4127 
• 5f Hanyu N. Aoki T. Mino T. Sakamoto M. Fujita T. Tetrahedron Lett.  2000,  41:  4587 
• 5g Nevalainen M. Nevalainen V. Tetrahedron: Asymmetry  2001,  12:  1771 
• 5h Martínez AG. Vilar ET. Fraile AG. de la Moya Cerero S. Maroto BL. Tetrahedron: Asymmetry  2003,  14:  1959 
• 6 The reaction of diethylzinc with benzaldehyde in the presence of the ligand 1c (20 mol%) has been reported to give (R)-1-phenylpropan-1-ol in 35% chemical yield with 82% ee: Oppolzer W. Radinov RN. Tetrahedron Lett.  1988,  29:  5645 
• 7 The β-amino alcohol-type ligand, (1R,2S)-dimethylamino-2-hydroxyapocamphone, has been reported to exhibit low enantioselectivity: Martínez AG. Vilar ET. Fraile AG. de la Moya Cerero S. Martínez-Ruiz P. Villas PC. Tetrahedron: Asymmetry  2002,  13:  1 
• 8 Bartlett PD. Knox LH. Org. Synth. Coll. Vol. V   Wiley; New York: 1973.  p.689-691  
• 9 Li X. Lou R. Yeung C.-H. Chan ASC. Wong WK. Tetrahedron: Asymmetry  2000,  11:  2077 
• 10 The synthesis of racemic compounds of 1a,c,d,h,i for evaluation of their anticonvulsant and antispasmodic activity has been reported: Schenone P. Tasca A. Bignardi G. Mosti L. Eur. J. Med. Chem.  1975,  10:  412 
• 11 Quaternary ammonium salts prepared from enantiomer of 1a have been used as phase-transfer catalysts: Zhang J. Wu X.-Y. Zhou Q.-L. Sun J. Chin. J. Chem.  2001,  19:  630 ; Chem. Abstr. 2001, 135, 241982h
• 12 It is known that an amino moiety of chiral amino alcohol-type ligands remarkably affects the enantioselectivity of the addition of diethylzinc to aldehydes, for instance, see: Soai K. Yokoyama S. Hayasaka T. J. Org. Chem.  1991,  56:  4264 
• 13 Kitamura M. Okada S. Soga S. Noyori R. J. Am. Chem. Soc.  1989,  111:  4028 
• 14 Guo P. Liu G.-L. Jiang Y.-Z. Zhou Z.-Y. Science in China, Series B  1991,  34:  385 ; Chem. Abstr. 1991, 115, 136416r