flash chromatography on silica gel (cyclohexane/EtOAC 8 : 2, as
eluent).
(-)-N-(2S,4R)-trans-(4-Phenyl-1,2,3,4-tetrahydronaphthalen-2-
yl)propionamide (1d). 1d was prepared according to the above
procedure starting from the azide (2S,4R)-9b. Yield 74%; white
solid, m.p. 149–150 ◦C; [a]D20 -51.3 (c 0.13, CHCl3); [a]H20g = -106.5◦
(c 0.13, CHCl3).
Enantiomeric excess was determined by HPLC on a Chiralcel
(Chiralpak) AD-H column, with hexane/iPrOH, 19 : 1 as eluent,
flux 1.0 mL min-1, l 262 nm; retention time = 10.1 min; ee
>99%. The physical-chemical properties were identical with those
previously reported for racemic mixture.25
(+)-(2S,4S)-4-Phenyl-1,2,3,4-tetrahydronaphthalen-2-yl meth-
anesulfonate (8a). 8a was prepared according to the above
procedure starting from the alcohol (-)-(2S,4S)-7a. Yield 80%;
oil; [a]2D0 = +11.1 (c 0.099 in CHCl3); [a]20 = +22.2◦ (c 0.099 in
Hg
CHCl3). Found: C 67.36; H 5.97%. Calc. for C17H18O3S: C 67.52;
H 6.00%.
NMR dH (200 MHz, CDCl3) 2.19 (1H, ddd, JH3aH4 = JH3aH2
JH3aH3b = 11.5 Hz, H3a), 2.64 (1H, ddd, JH3bH2 = 3.0 Hz, JH3bH3a
11.5 Hz, H3b), 3.04 (3H, s, OSO2CH3), 3.24 (1H, dd, JH1aH2
=
=
=
10.0 Hz, JH1aH1b = 15.5 Hz, H1a), 3.40 (1H, dd, JH1bH2 = 5.0 Hz,
JH1bH1a = 15.5 Hz, H1b), 4.24 (1H, dd, JH4H3b = 5.5 Hz, JH4H3a
11.5 Hz, H4), 5.18 (1H, dddd, JH2H1b = 5.0 Hz, JH2H1a = 10.0 Hz,
JH2H3a = 11.5 Hz, JH2H3b = 3.0 Hz, H2), 6.78 (1H, d, J = 7.5 Hz,
ArH), 7.23 (8H, m, ArH); dC (50 MHz, CDCl3) 36.8, 38.8, 39.8,
45.6, 77.4, 126.7, 126.74, 126.8, 128.67, 128.7, 129.1, 129.3, 133.1,
138.0, 144.9; ESI-MS: m/z 303 (M+1).
Acknowledgements
=
This work was supported by the Italian M.I.U.R. (Ministero
dell’Istruzione, dell’Universita` e della Ricerca).
Notes and references
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(-)-(2R,4R)-4-Phenyl-1,2,3,4-tetrahydronaphthalen-2-yl meth-
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oil; [a]20 -10.1 (c 0.089 in CHCl3); [a]20 = -20.2◦ (c 0.089 in CHCl3).
D
Hg
Found: C 67.31; H 5.96%. Calc. for C17H18O3S: C 67.52; H 6.00%.
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(+)-N-(2R,4S)-trans-(4-Phenyl-1,2,3,4-tetrahydronaphthalen-2-
yl)propionamide (1c). 1c was prepared according to the above
procedure starting from the azide (2R,4S)-9a. Yield 70%; white
◦
solid, m.p. 151–152 C; [a]2D0 = +49.5 (c 0.13, CHCl3); [a]2H0g
=
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Enantiomeric excess was determined by HPLC on a Chiralcel
(Chiralpak) AD-H column, with hexane/iPrOH, 19 : 1 as eluent,
flux 1.0 mL min-1, l 262 nm; retention time = 13.6 min; ee
>99%. The physical-chemical properties were identical with those
previously reported for racemic mixture.25
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312 | Org. Biomol. Chem., 2012, 10, 305–313
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