8073
11. For an excellent discussion of stereochemical models for 1,2- and 1,3-asymmetric induction, see: Evans, D. A.;
Dart, M. J.; Duffy, J. L.; Yang, M. G. J. Am. Chem. Soc. 1996, 118, 4322–4343.
12. Racherla, U. S.; Brown, H. C. J. Org. Chem. 1991, 56, 401–404.
13. This result was unexpected in light of the usually observed chelation-controlled anti-addition product with TiCl4
as the Lewis acid; see for example: Reetz, M. T.; Jung, A. J. Am. Chem. Soc. 1983, 105, 4833–4835; Keck, G.
E.; Castellino, S. ibid. 1986, 108, 3847–3849. On the contrary, reaction of aldehyde 11 with allyltrimethylsilane
in the presence of BF3·Et2O or SnCl4 as Lewis acids gave primarily the expected anti-diastereomer (anti:syn>
95:5).
1
14. Compound 4: [h]D=+6.8 (MeOH, c 0.16); IR 3262, 2924, 1711, 1584, 1463, 1288, 1085, 755 cm−1; H NMR (400
MHz, acetone-D6) l 8.36 (1H, s), 7.11 (1H, dd, J=7.6, 8.0 Hz), 6.77 (1H, d, J=8.0 Hz), 6.70 (1H, d, J=7.6 Hz),
5.92 (1H, dddd, J=6.4, 7.6, 10.4, 17.6 Hz), 5.48 (1H, dddd, J=2.4, 5.6, 5.6, 10.0 Hz), 5.14 (1H, dddd, J=1.6,
1.6, 2.4, 17.6 Hz), 5.03 (1H, dddd, J=1.6, 1.6, 2.4, 10.4 Hz), 4.27 (1H, dddd, J=2.0, 5.0, 7.0, 10.8 Hz), 3.99 (1H,
ddddd, J=4.0, 4.1, 5.1, 7.6, 8.8 Hz), 3.88 (1H, dddd, J=1.2, 4.8, 8.0, 10.0 Hz), 3.77 (1H, d, J=4.0 Hz), 3.34 (1H,
dd, J=9.6, 15.2 Hz), 2.44 (1H, dd, J=1.6, 15.2 Hz), 2.28–2.44 (2H, m), 1.93 (1H, ddd, J=4.8, 4.8, 12.8 Hz), 1.83
(1H, ddd, J=10.8, 10.8, 14.4 Hz), 1.68 (1H, ddd, J=5.2, 7.2, 12.8 Hz), 1.58 (1H, ddd, J=2.0, 2.4, 14.4 Hz), 1.52
(1H, ddd, J=4.4, 7.2, 12.8 Hz), 1.49 (1H, ddd, J=8.4, 8.4, 12.8 Hz); 13C NMR (75 MHz, acetone-D6) l 169.8,
161.2, 154.8, 140.1, 135.9, 130.8, 122.9, 118.0, 114.9, 74.2, 74.1, 68.6, 65.4, 40.9, 40.6, 40.5, 40.3, 39.6; MS (CI)
1
318 [M+], 301, 283, 251, 231, 207, 163, 134, 97, 94. Compound 16: H NMR (400 MHz, acetone-D6) l 8.40 (1H,
s), 7.14 (1H, dd, J=7.6, 8.0 Hz), 6.79 (1H, d, J=8.0 Hz), 6.76 (1H, d, J=7.6 Hz), 5.91 (1H, dddd, J=7.2, 7.2,
10.4, 17.2 Hz), 5.50 (1H, dddd, J=4.0, 5.6, 7.2, 10.0 Hz), 5.14 (1H, dddd, J=1.6, 1.6, 2.0, 17.2 Hz), 5.04 (1H,
dddd, J=1.2, 1.2, 2.0, 10.4 Hz), 3.97–4.04 (1H, m, DJ=24.8 Hz), 3.87–3.96 (2H, m), 3.73 (1H, d, J=4.8 Hz), 3.32
(1H, dd, J=11.6, 14.0 Hz), 2.33–2.38 (2H, m), 2.34 (1H, dd, J=1.6, 14.0 Hz), 1.67–1.91 (4H, m), 1.64 (1H, ddd,
J=6.4, 9.6, 13.2 Hz), 1.20 (1H, ddd, J=9.2, 10.8, 12.4 Hz); 13C NMR (75 MHz, acetone-D6) l 171.0, 154.4,
141.3, 135.8, 131.0, 126.4, 122.8, 118.0, 114.9, 76.3, 74.4, 68.8, 66.0, 42.5, 41.8, 40.2, 40.0, 37.6.
.