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

Experimental for chapter 4.1
¹³C-NMR (CD 3 OD, 75.5 MHz) δ 77.7 (CHOH), 76.3 (CHOH), 74.0 (CHOH), 72.6
(CHOH), 65.8 (C7), 49.4 (C2), 45.3 (C1), 27.5 (CHMe 2 ), 26.9, 21.8, 18.7 (Me).
Synthesis of (1S,2R,3S,4R,5R,6S)-5-(N-methyl-(4R,5R)-4,5-diphenyloxazolidin-2-
yl)-3,4-epoxy-6-isopropyl-5-methylcyclohexane-1,2-diol (306) and
(1S,2R,3S,4R,5R,6S)-2,3-epoxy-5-hydroxy-6-isopropyl-1-methylcyclohexane-δlactone
(307)
Ph Ph
Ph Ph
O
O
OH
N
OH
O NMe
MeOTf, then NaBH 4
Me
1
1
6 2 O
2
O
O
3
O
5 4 OH
4
OH
306 307
3
OH
General procedure 6 was used employing oxazoline 216 (101 mg, 0.25 mmol) and
methyl triflate (56 µl, 0.50 mmol) for 16 hr. The solvent was removed, the aqueous
layer washed with CH 2 Cl 2 (2 x 10 cm 3 ) and the combined organic phases dried over
anhydrous sodium sulfate. Flash chromatography (9:1 to 1:1 petrol:EtOAc) gave
oxazolidine 306 (39 mg, 40%) and oxazolidine 307 (15 mg, 30%) as colourless oils.
306 R f : 0.21 (2:1, petrol:EtOAc); [α] 23 D : +72 (c = 1.3, CHCl3); MS m/z (ES+) 424
(23%, MH + ), 446 (100%, MNa + ), 447 (32%, (M+1)Na + ), 869 (40%, M 2 Na + ); HRMS:
found 424.2483, MH requires 424.2482; IR ν max (film)/cm⎯¹ 3392 (br, O-H), 2928 (m,
C-H), 2357 (m), 1456 (m, C-Me), 1068 (C-O-C); ¹H-NMR (CDCl 3 , 500 MHz) δ 7.31-
7.28 (m, 5H, Ph), 7.26-7.22 (m, 2H, Ph), 7.21-7.16 (m, 1H, Ph), 7.11-7.07 (m, 2H, Ph),
5.36 (d, 1H, J 9.5, CHOPh), 4.71 (s, 1H, CHNO), 4.16 (dd, 1H, J 11.5, 8.0H3), 3.68
(dd, 1H, J 8.0, 1.5H4), 3.49 (d, 1H, J 4.0, H6), 3.43 (dd, 1H, J 4.0, 1.5, H5), 3.34 (d,
1H, J 9.5, CHNPh), 2.41 (s, 3H, NMe), 2.16 (m, 1H, CHMe 2 ), 1.34 (d, 3H, J 7.0,
CHMe A Me b ), 1.29-1.26 (m, 4H, Me, H2), 1.18 (d, 3H, J 7.0, CHMe a Me B ); ¹³C-NMR
(CDCl 3 , 75.5 MHz) δ 139.9 (ipso-Ph), 138.2 (ipso-Ph), 128.6, 128.3, 128.0, 127.8,
127.4, 126.1 (Ph), 101.5 (CHNO), 85.4 (CHOPh), 81.0 (CHNPh), 77.3 (C4), 72.0
(C3), 61.0 (C6), 56.6 (C2), 55.3 (C5), 43.6 (C1), 42.1 (NMe), 27.6 (CHMe a Me B ), 26.4
(CHMe 2 ), 24.9 (Me), 17.8 (CHMe A Me b ).
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