Synthesis of (R)-aryloxy acids by SN2 reaction from diastereomerically enriched α-bromo esters

Synlett

Volumn , Issue 4, 1998, Pages 363-364

  Amoroso, Rosa ^a   Bettoni, Giancarlo ^a   Tricca, Maria Luisa ^a  

^a UNIVERSITY OF CHIETI   (Italy)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 0002893037     PISSN: 09365214     EISSN: None     Source Type: Journal    
DOI: 10.1055/s-1998-1662     Document Type: Article

References (12)

1. Koh, K.; Durst, T. J. Org. Chem. 1994, 59, 4683.
2. Ward, R. S. Tetrahedron: Asymmetry 1995, 6, 1475.
3. The descriptors (R) and (S) refer to the α-bromo stereogenic center, whereas the one of pantolactone is omitted for clarity.
4. Amoroso, R.; Bettoni, G; Tricca, M. L.; Loiodice, F.; Ferorelli, S. Il Farmaco, in press.
5. Durst, T.; Koh, K. Tetrahedron Lett. 1992, 33, 6799.
6. 2O and concentrated in vacuo to afford (S)-2a-b as oil (2.4 mmol, 89 %yield, 95% de).
7. 2O 2:1, and the optical rotations of the corresponding α-bromo acids compared with the literature values.
8. 4 and concentrated in vacuo. The residue was purified by column chromatography on silica gel eluting with cyclohexane-ethyl acetate 9:1 to give a diastereomeric mixture of 3a-b.
9. 1H NMR data for 3a (mixture of diastereomers): δ 0.93, 1.05, 1.16 (each s, 6H), 1.68 (dd, 3H), 4.00 (dab, 2H), 4.85 (dq, 1H), 5.34 and 5.35 (both s, 1H), 6.79-7.25 (m, 4H).
10. 1H NMR data for 3b (mixture of diastereomers): δ 0.93, 1.03, 1.06 and 1.16 (each s, 6H), 1.11 (dt, 3H), 1.98-2.13 (m, 2H), 4.00 (dab, 2H), 4.66 (dd, 1H), 5.36 and 5.37 (both s, 1H), 6.81-7.24 (m, 4H).
11. 1H NMR data for (R)-3b: δ 1.06 (s, 3H), 1.11 (t, 3H), 1.16 (s, 3H), 2.00-2.09 (m, 2H), 4.01 (ab, 2H), 4.65 (dd, 1H), 5.36 (s, 1H), 6.80-7.24 (m, 4H).
12. Ward, R. S.; Pelter, A.; Goubet, D.; Pritchard, M. C.; Tetrahedron: Asymmetry 1995, 6, 469.