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

Experimental for chapter 3.1
Synthesis of (S)-4-isopropyl-2-phenyloxazoline (111a)
O NH 2 i) (Et 3 O)BF 4
ii)
HO
H 2 N
O
N
General procedure 3 was used mixing benzamide (400 mg, 3.30 mmol) with the
triethyloxonium salt (690 mg, 3.63 mmol) stirring for 24 hr, before addition of the
amino alcohol (0.44 cm 3 , 3.96 mmol) and reflux for 21 hr. Purification by flash
chromatography (9:1 petrol:EtOAc), yielded oxazoline 111a (510 mg, 82%) as a clear
oil.
R f : 0.44 (4:1 petrol:EtOAc); [α] 24 D : –46 (c = 0.6, EtOH); MS m/z (CI+): 190 (100%,
MH + ), 191 (9%, (M+1)H + ); HRMS (ESI+) m/z found 190.1227 (MH calcd. 190.1226);
IR ν max (film)/cm -1 : 2960 (C-H), 1649 (C=N), 1450 (w), 1353 (m); 1 H-NMR (CDCl 3 ,
300 MHz) δ 7.99-7.92 (m, 2H, ortho-Ph), 7.50-7.35 (m, 3H, Ph), 4.45-4.35 (m, 1H,
CHN), 4.17-4.04 (m, 2H, CH 2 ), 1.93-1.79 (m, 1H, CHMe 2 ), 1.03 (d, 3H, J 7.0,
CHMe a Me b ), 0.92 (d, 3H, J 7.0, CHMe a Me b ); 13 C-NMR (CDCl 3 , 75 MHz) δ 163.3
(C=O), 131.1, 128.2, 128.2 (Ar), 127.8 (ipso-Ph), 72.5 (CO), 70.0 (CN), 32.8
(CHMe 2 ), 18.9 (CHMe a Me b ), 18.0 (CHMe a Me b ).
Synthesis of (S)-4-isopropyl-2-(4-methoxyphenyl)oxazoline (111b)
O NH 2
i) (EtO) 3 BF 4
O
N
OMe
1
ii)
HO
4
H 2 N
OMe
2
3
General procedure 3 was used mixing p-anisamide (451 mg, 2.98 mmol) with the
triethyloxonium salt (651 mg, 3.43 mmol) and stirred for 26 hr before addition of the
α-amino alcohol (400 mg, 3.88 mmol) and refluxed for 16 hr. Purification by flash
chromatography (4:1 petrol:EtOAc) yielded oxazoline 111b (382 mg, 58%) as a clear
oil.
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