Diastereo- and enantioselective tandem Michael addition and lactonization catalyzed by chiral quaternary ammonium phenoxide: Stereoselective synthesis of the two enantiomers by using a single chiral source

Chemistry Letters

Volumn 35, Issue 8, 2006, Pages 916-917

  Mukaiyama, Teruaki ^a,b   Nagao, Hitoshi ^a,b   Yamane, Yoshinobu ^a,b  

^a KITASATO INSTITUTE   (Japan)

^b KITASATO UNIVERSITY   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 33750706200     PISSN: 03667022     EISSN: None     Source Type: Journal    
DOI: 10.1246/cl.2006.916     Document Type: Article

References (5)

1. a) T. Tozawa, Y. Yamane, T. Mukaiyama, Chem. Lett. 2006, 35, 56.
2. b) T. Tozawa, Y. Yamane, T. Mukaiyama, Chem. Lett. 2006, 35, 360.
3. For the preparation and X-ray crystallographic analysis of quaternary ammonium p-nitrophenoxide, see: E. J. Corey, F. Xu, M. C. Noe, J. Am. Chem. Soc. 1997, 119, 12414.
4. Structural assignment of diastereomeric 3,4-dihydropyran-2-ones was based on the ' H NMR chemical shift of the characteristic vinyl proton, which resonates at a lower magnetic field in the cis isomer than in the trans isomer. see: T. Tozawa, Y. Yamane, T. Mukaiyama, Chem. Lett. 2005, 34, 514.
5. 3) δ 7.68-7.65 (m, 2H), 7.40-7.36 (m, 3H), 7.15 (d, J = 8.6 Hz, 1H), 6.87 (d, J = 8.6 Hz, 1H), 5.83 (d, J = 4.6 Hz, 1H), 3.80 (s, 3H), 3.68 (dd, J = 7.2 Hz, 4.6 Hz, 1H), 2.70 (dd, J = 12.9 Hz, 7.2 Hz, 1H), 1.77-1.67 (m, 2H), 1.04 (t, J = 7.4 Hz, 3H). The enantiomeric excess was determined by HPLC analysis using DAICEL Chiralcel OD-H, hexane/2-propanol = 50/1, λ = 254 nm, flow rate = 1.0 mL/min, retention time = 15.1 min (major) and 17.3 min (minor).