recovered naphthamide 18B (34 mg, 16%). Heating amine 20 in
CDCl3 for 2 d at 60 C produced a ratio of atropisomers 1.7 : 1
(1H NMR); epi-20, dH(300 MHz, CDCl3) 1.96 (6H, s, NMe2).
(27%, M–C19H28NO) and 286 (16%, M–C18H29N2O); m/z (EI) 289
(1%, M–C19H28NO) and 49 (100%) (found: M + H+, 576.4524.
C37H57N3O2 requires M + H, 576.4529).
◦
(aRꢀ)-N,N-Diisopropyl-2-[(1Sꢀ,2Sꢀ)-2-{(aRꢀ)-(diisopropylamino)-
carbonyl]-3-ethylphenyl}-1-methyl-2-(dimethylaminoborane)ethyl]-
1-naphthamide (21). A solution of naphthamide 20 (132 mg,
0.23 mmol) in THF (2 ml) at 0 ◦C under an atmosphere of
nitrogen was treated with borane (0.46 ml, 0.46 mmol; 1 M
solution in THF) and stirred for a further 40 min. The solvent was
removed at ambient temperature under reduced pressure, and the
crude product was purified by flash chromatography on silica gel
[1 : 1 petrol (bp 40–60 ◦C)–EtOAc] to afford pure amine–borane
complex 21 (97 mg, 72%) as a white solid, mmax (film)/cm−1 3053,
2976, 2934, 2875, 2395, 2334, 2285, 1615; dH(300 MHz, CDCl3)
7.89 (1H, d, J 8.8, ArH), 7.78 (1H, d, J 8.8, ArH), 7.74–7.64
(2H, m, ArH), 7.36 (3H, m, ArH), 7.23 (1H, t, J 7.7, ArH),
7.13 (1H, d, J 7.4, ArH), 4.88 (1H, d, J 9.6, CHN+Me2), 3.81
(1H, septet, J 6.3, NCH), 3.64–3.40 (4H, m, CH(Me)CHN+Me2
and 3 × NCH), 2.86 (3H, s, +NMe), 2.74 (1H, m, CHHMe),
2.61 (1H, m, CHHMe), 2.32 (3H, s, +NMe), 1.71 (9H, m, 3 ×
CHCH3), 1.62 (3H, d, J 6.7, CHCH3), 1.50 (3H, bs, BH3) 1.12
(3H, d, J 6.3, CHCH3), 1.08 (3H, d, J 6.5, CHCH3), 1.06 (3H, t,
J 7.6, CH2CH3), 0.95 (3H, d, J 6.6, CHCH3), 0.89 (3H, d, J 6.5,
CHCH3), 0.72 (3H, d, J 7.0, CHCH3); dC(75 MHz, CDCl3) 169.9,
169.9, 141.3, 141.1, 138.3, 136.6, 132.0, 130.8, 129.7, 129.0, 128.0,
127.7, 127.6, 126.5, 125.9, 125.8, 125.0, 124.6, 74.6, 55.3, 50.7,
50.3, 46.8, 46.3, 46.2, 38.0, 29.6, 27.6, 23.1, 21.7, 21.3, 21.1, 20.9,
20.8, 20.7, 20.2, 20.1 and 16.5; m/z (CI) 572 (100%, M–BH3);
m/z (EI) 572 (1%, M–BH3) and 49 (100%).
Acknowledgements
We are grateful to Dr Francis Wilson for many illuminating
discussions, and to EPSRC and Roche for support.
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mmax (film)/cm−1 2973, 2934, 2874, 1625; dH(200 MHz, CDCl3)
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