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

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Experimental for chapter 4.1<br />

2.30 (br s, 1H, OH), 2.10 (pd, 1H, J 7.0, 1.0, CHMe 2 ), 1.99 (dd, 1H, J 11.0, 1.0, H2),<br />

1.53 (s, 3H, Me), 1.11 (d, 3H, J 7.0, CHMe A Me b ), 1.01 (d, 3H, J 7.0, CHMe a Me B ); ¹³C-<br />

NMR (CDCl 3 , 75.5 MHz) δ 169.4 (C=N), 141.4 (ipso-Ph), 139.5 (ipso-Ph), 139.2<br />

(ipso-Ph), 138.5 (ipso-Ph), 129 (para-Ph), 128.9 (Ph), 128.8 (Ph), 128.7 (Ph), 128.5<br />

(para-Ph), 128.2 (Ph), 128.2 (para-Ph), 127.9 (Ph), 127.7 (para-Ph), 127.1, 127,<br />

126.6, 126.1 (Ph), 88.8 (CHOPh), 85.9 (CHOR), 80.1 (CHOR), 78.2 (CHNPh), 75.6<br />

(OBn), 75.1 (CHOR), 72.8 (OBn), 71.9 (CHOR), 49.1 (C2), 45.7 (C1), 27.6 (CHMe 2 ),<br />

26.7 (Me), 22.4 (CHMe A Me b ), 19.5 (CHMe a Me B ).<br />

Synthesis of (1R,2S,3S,4S,5R,6S)-2,3,4,5-tetra(benzyloxy)-1-((4R,5R)-4,5-<br />

diphenyloxazolin-2-yl)-6-isopropyl-1-methylcyclohexane (302)<br />

HO<br />

HO<br />

Ph<br />

O<br />

N<br />

OBn<br />

Ph<br />

OBn<br />

BnBr, DMF, NaH<br />

n-Bu 4 NI<br />

BnO<br />

BnO<br />

Ph<br />

5<br />

O<br />

6<br />

1<br />

N<br />

Ph<br />

2<br />

OBn<br />

3<br />

4 OBn<br />

BnO<br />

HO<br />

Ph<br />

5<br />

O<br />

6<br />

1<br />

N<br />

Ph<br />

2<br />

3<br />

4 OBn<br />

OBn<br />

Adapted from the method of Provelenghi, 19 sodium hydride (5 mg, 0.12 mmol) was<br />

added slowly <strong>to</strong> a solution of benzyl bromide (20 µl, 0.15 mmol), diol 300 (23 mg,<br />

0.04 mmol) and tetrabutylammonium iodide (1 mg, 0.003 mmol) in DMF (0.8 cm 3 )<br />

whilst the reaction mixture was maintained at ambient temperature. When the reaction<br />

was judged complete (c. 16 hr) aqueous ammonium chloride (saturated, 0.1 cm 3 ) was<br />

added <strong>to</strong> the reaction, the solvent removed under vacuum and the resulting residue<br />

partitioned between water (2 cm 3 ) and CH 2 Cl 2 (6 cm 3 ). <strong>The</strong> aqueous phase was<br />

washed with further CH 2 Cl 2 (2 x 5 cm 3 ) and the combined organic phases dried over<br />

sodium sulphate, before purification by flash chroma<strong>to</strong>graphy (19:1 <strong>to</strong> 9:1<br />

petrol:EtOAc) yielded alcohol 301 (14 mg, 54%), perbenzyl ether 302 (10 mg, 33%)<br />

and starting material (2 mg, 9%) as colourless oils.<br />

302 R f : 0.45 (9:1, petrol:EtOAc); [α] 24 D : +21 (c = 1, CHCl 3 ); MS m/z (ES+) 786<br />

(67%, MH + ), 808 (100%, MNa + ), 809 (52%, (M+1)Na + ); HRMS: found 786.4159,<br />

MH requires 786.4153; IR ν max (film)/cm⎯¹ 2930 (m, C-H), 1453 (m, C-Me), 1069; ¹H-<br />

NMR (CDCl 3 , 500 MHz) δ 7.36-7.10 (m, 30H, Ph), 5.20 (d, 1H, J 11.5, CHOPh), 5.12<br />

(s, 2H, OBn), 5.09 (d, 1H, J 11.5, CHNPh), 5.01 (d, 1H, J 10.5, OBn), 4.79-4.71 (m,<br />

257

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