Chiral azabicyclo-N-oxyls mediated enantioselective electrooxidation of sec-alcohols

Tetrahedron Letters

Volumn 49, Issue 36, 2008, Pages 5247-5251

  Shiigi, Hirofumi ^a   Mori, Hiroyuki ^a   Tanaka, Tomoaki ^a   Demizu, Yosuke ^a   Onomura, Osamu ^a  

^a NAGASAKI UNIVERSITY   (Japan)

Author keywords

Chiral nitroxyl radical; Electrooxidation; Enantioselective oxidation; Optically active alcohol

Indexed keywords

2,2,6,6 TETRAMETHYLPIPERIDINE 1 OXYL; HYDROXYPROLINE; PIPERIDINE DERIVATIVE;

ARTICLE; BENZYLATION; CATALYSIS; CHIRALITY; CYCLIZATION; ENANTIOSELECTIVITY; OXIDATION; POTENTIOMETRY;

EID: 47549091896     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tetlet.2008.06.112     Document Type: Article

References (23)

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11. Demizu Y., Shiigi H., Oda T., Matsumura Y., and Onomura O. Tetrahedron Lett. 49 (2008) 48-52
12. 2 symmetrical azabicyclo-N-oxyls with low enantioselectivities (s value: up to 2.5):. Graetz B., Rychnovsky S., Leu W., Farmer P., and Lin R. Tetrahedron: Asymmetry 16 (2005) 3584-3598
13. + 220.0740: found 220.0735.
14. The optical purity of 5 was determined after conversion to 1-naphthoylated N-oxyl 7g by chiral HPLC: Daicel Chiralcel OD-H column (4.6 mm∅, 250 mm), n-hexane/isopropanol = 5:1, wavelength: 254 nm, flow rate: 1.0 mL/min, retention time: 12.3 min for (6R)-7g, 17.4 min for (6S)-7g.
15. The stereoconfiguration for 6g was deduced by NOE correlation. {A figure is presented}
16. + 330.0897; found 330.0899.
17. 3 as a reference electrode. Concentration of 7g: 1.0 mM. Scan rate: 30 mV/s. Cyclic voltammogram for other O-acyloxylated N-oxyls 7b-f,h-m showed reversible wave pattern similar to that for 7g, while that for hydroxylated N-oxyls 7a was irreversible.
18. 12
19. The optical purity of (S)-8 was determined by chiral HPLC: Daicel Chiralcel OB column (4.6 mm∅, 250 mm), n-hexane/isopropanol = 15:1, wavelength: 254 nm, flow rate 0.5 mL/min, retention time: 13.5 min for (S)-8, 17.5 min for (R)-8.
20. dl-8 was oxidized in the absence of N-oxyl to afford 9 with 16% yield.
21. Kagan H.B., and Fiaud J.C. In: Eliel E.L. (Ed). Topics in Stereochemistry Vol. 18 (1988), Wiley & Sons, New York 249-330
22. 4-catalyzed cyclization of 4.
23. A precursor for N-oxyl 7m was synthesized by reductive dechlorination of 5.