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

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Experimental for chapter 4.1<br />

Ph), 7.22-7.18 (m, 2H, Ph), 6.78 (d, 1H, J 10.0, H6), 6.18 (d, 1H, J 10.0, H5), 5.22 (d,<br />

1H, J 10.5, CHO), 5.09 (d, 1H, J 10.5, CHN), 4.68 (dd, 1H, J 13.0, 2.0, H3), 3.62* (d,<br />

1H, J 2.0, OH), 2.40 (p, 1H, J 7.5, CHMe 2 ), 1.99 (d, 1H, J 13.0, H2), 1.63 (s, 3H, Me),<br />

1.70 (d, 3H, J 7.5, CHMe a Me b ), 1.15 (d, 3H, J 7.5, CHMe a Me b ); 13 C-NMR (CDCl 3 ,<br />

100 MHz) δ 201.7 (C=O), 167.4 (C=N), 153.9 (C6), 140.5 (ipso-Ph), 138.5 (ipso-Ph),<br />

129.0, 128.9, 128.8, 127.9, 126.7, 126.2, 124.7 (Ph), 90.1 (CHO), 77.9 (CNH), 55.2<br />

(COH), 44.1 (C1), 27.1 (CHMe 2 ), 25.9 (CHMe a Me b ), 25.5 (CHMe a Me b ), 17.3 (Me).<br />

283 R f : 0.18 (4:1 petrol:EtOAc); [α] 21 D : +197.5 (c = 2.1, CHCl 3 ); MS m/z (CI+): 388<br />

(100%, MH + ), 389 (27%, (M+1)H + ), 194 (70%, [M-Ph 2 CHO]H + ); HRMS (ESI+) m/z<br />

found 388.1911 (MH calcd. 388.1907); IR ν max (film)/cm -1 : 3391 (m, O-H), 2931 (w,<br />

C-H), 1643 (C=O); 1 H-NMR (CDCl 3 , 300 MHz) δ 7.43-7.26 (m, 8H, Ph), 7.24-7.18<br />

(m, 2H, Ph), 7.04 (d, 1H, J 10.0, H6), 6.64 (s, 1H, OH), 6.49 (d, 1H, J 10.0, H5), 5.23<br />

(d, 1H, J 8.5, CHO), 5.18 (d, 1H, J 8.5, CHN), 2.61 (p, 1H, J 2.5, CHMe 2 ), 1.75 (s,<br />

3H, Me), 1.34 (d, 3H, J 7.0, CHMe a Me b ), 1.28 (d, 3H, J 7.0, CHMe a Me b ); 13 C-NMR<br />

(CDCl 3 , 75 MHz) δ 181.1 (C4), 167.1 (C=N), 152.8, 145.1 (C3, C6), 141.2 (ipso-Ph),<br />

138.8 (ipso-Ph), 136.0 (C5), 128.9 (meta-Ph), 128.9 (meta-Ph), 127.9 (para-Ph), 126.6<br />

(ortho-Ph), 126.5 (ortho-Ph), 125.6 (C2), 90.3 (CHO), 77.6 (CHN), 46.9 (CMe), 30.4<br />

(CHMe 2 ), 22.9 (Me), 19.9 (CHMe a Me b ), 19.4 (CHMe a Me b ).<br />

Synthesis of (1R,2R,5S,6S)-5-((4R,5R)-4,5-diphenyloxazolin-2-yl)-6-isopropyl-5-<br />

methylcyclohex-3-ene-1,2-diol (213)<br />

Ph Ph<br />

Ph Ph<br />

O<br />

N<br />

O<br />

N<br />

NaBH 4<br />

EtOH, 0 °C<br />

OH<br />

O<br />

6<br />

5<br />

1<br />

2<br />

3<br />

4 OH<br />

OH<br />

Sodium borohydride (24 mg, 0.63 mmol) was added in a single portion <strong>to</strong> a stirred<br />

solution of enone 276 (220 mg, 0.57 mmol) in ethanol (6 cm 3 ) at 0 °C. When judged<br />

complete by TLC (PMA stain c. 6 hr) acetic acid was added <strong>to</strong> the cooled reaction<br />

mixture until effervescence ceased and warmed <strong>to</strong> room temperature. <strong>The</strong> solvent was<br />

removed from the reaction mixture, which was partitioned between water (10 cm 3 ) and<br />

CH 2 Cl 2 (20 cm 3 ) and the aqueous layer further washed (2 x 20 cm 3 CH 2 Cl 2 ) and the<br />

249

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