A Route to Carbasugar Analogues - Jonathan Clayden - The ...

Experimental for chapter 4.1
5.5 Experimental Procedures for Chapter 4.1
Synthesis of (2S,3S,4R,5S)-4-((4R,5R)-4,5-diphenyloxazolin-2-yl)-2,3-dihydroxy-5-
isopropyl-4-methylcyclohexanone (280)
Ph Ph
Ph Ph
Ph Ph
O
N
O
N
O
N
OsO 4 , NMO, CH 2 Cl 2
280 281
HO
6
1
2
HO
6
1
2
O
HO
5
O
4
3
HO
5
O
4
3
General procedure 5 was employed using enone (100 mg, 0.27 mmol), OsO 4 (0.6 mg,
0.003 mmol), NMO monohydrate (73 mg, 0.54 mmol), in CH 2 Cl 2 (5 cm 3 ). Upon
completion, sodium sulfite (0.5 cm 3 , sat. aq.) was added. Purification by flash
chromatography (9:1 to 2:1 petrol:EtOAc) yielded diol 280 (57 mg, 55%) as a
colourless foam, and diol 281 (3 mg, 2%) and starting material (11 mg, 11%) as a
colourless oil.
280 R f : 0.39 (1:1 petrol:EtOAc); [α] 25 D : +36 (c = 1.0, CH 2 Cl 2 ); MS m/z (CI+): 408
(100%, MH + ), 409 (24%, (M+1)H + ); HRMS (ESI+) m/z found 408.2170 (MH calcd.
408.2169); IR ν max (film)/cm -1 : 3470 (br, O-H), 2952 (m, C-H), 1719 (C=O), 1453 (m);
1 H-NMR (DMSO, 500 MHz) δ 7.36 (m, 2H, ortho-Ph), 7.45 (t, 2H, J 7.5, meta-Ph),
7.40-7.38 (m, 3H, Ph), 7.32 (tt, 1H, J 7.5, 2.0, para-Ph), 7.32 (d, 2H, J 7.5, ortho-Ph),
5.49 (d, 1H, J 4.5, C6OH), 5.25 (d, 1H, J 9.0, CHO), 5.14 (d, 1H, J 9.0, CHN), 5.00
(dd, 1H, J 7.0, 3.5, H5), 4.72 (d, 1H, J 7.0, C5OH), 4.04 (t. 1H, J 4.0, H6), 2.76 (t, 1H,
J 13.5, H3 axial ), 2.18 (dd, 1H, J 13.5, 4.0, H3 eq ), 2.12 (pd, 1H, J 7.0, 2.5, CHMe 2 ), 2.01
(ddd, 1H, J 14.0, 4.0, 2.5, H2), 1.42 (s, 3H, Me), 0.94 (d, 3H, J 7.0, CHMe a Me b ), 0.83
(d, 3H, J 7.0, CHMe a Me b ); 13 C-NMR (DMSO, 125 MHz) δ 209.9 (C=O), 168.6
(C=N), 141.5 (ipso-Ph), 139.7 (ipso-Ph), 129.1 (meta-Ph), 128.8 (meta-Ph), 128.7
(para-Ph), 127.3 (para-Ph), 126.6 (ortho-Ph), 126.4 (ortho-Ph), 126.3 (ortho-Ph), 87.3
(CHO), 79.3 (C6), 77.4 (CHN), 75.5 (C5), 46.2 (C1), 45.4 (C2), 37.8 (C3), 26.6
(CHMe 2 ), 24.6 (CHMe a Me b ), 21.6 (Me), 18.5 (CHMe a Me b ).
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