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G. E. Keck, M. D. McLaws / Tetrahedron Letters 46 (2005) 4911–4914
1
22. All new compounds were characterized by IR, H NMR,
13C NMR, and mass data. Spectroscopic and physical
characterization data of selected compounds: Compound
ꢀ3.7, ꢀ4.1; IR (neat) 3456 (broad), 2931, 1456, 1254,
1097, 836, 773 cmꢀ1. Anal. Calcd for C26H46O3Si requires
C, 71.83; H, 10.67. Found: C, 72.10; H, 10.65. Compound
20
20
5: Rf = 0.40 (15% EtOAc/hexanes); ½aꢁD +10.2 (c 0.95,
17: Rf = 0.38 (25% EtOAc/hexanes); ½aꢁD +22.5 (c 1.63,
CHCl3); 300 MHz 1H NMR (CDCl3) d 9.74 (t, J = 1.8 Hz,
1H), 7.35–7.26 (m, 5H), 4.49 (ABq, JAB = 11.9 Hz,
Dv = 14.4 Hz, 2H), 3.59–3.46 (m, 2H), 3.30 (dd, J = 8.9,
7.4 Hz, 1H), 2.55–2.30 (m, 2H), 2.04–1.89 (m, 1H), 1.78–
1.42 (m, 3H), 0.97 (d, J = 6.9 Hz, 3H), 0.89 (s, 9H), 0.87
(d, J = 6.9 Hz, 3H), 0.04 (s, 6H); 75 MHz 13C NMR
(CDCl3) d 202.6, 138.7, 128.3, 127.5, 127.4, 76.9, 73.0,
72.9, 42.3, 37.9, 35.9, 26.8, 26.1, 18.4, 15.0, 14.1, ꢀ3.8,
ꢀ4.1; IR (neat) 2931, 1726, 1458, 1254, 1097, 1057, 774,
698 cmꢀ1. Anal. Calcd for C22H38O3Si requires C, 69.79;
H, 10.12. Found: C, 69.52; H, 10.27. Compound 7:
CHCl3); 300 MHz 1H NMR (CDCl3) d 7.34–7.19 (m, 7H),
6.85 (d, J = 8.5 Hz, 2H), 5.82 (ddd, J = 16.0, 10.5, 5.5 Hz,
1H), 5.25 (app dt, J = 17.2, 1.4 Hz, 1H), 5.12 (app dt,
J = 10.5, 1.4 Hz, 1H), 4.57–4.35 (m, 5H), 3.90–3.84 (m,
1H), 3.78 (s, 3H), 3.53 (dd, J = 9.16, 4.7 Hz, 1H), 3.48 (dd,
J = 6.1, 2.7 Hz, 1H), 3.28, (dd, J = 8.7, 7.6 Hz, 1H), 3.10
(br d, J = 3.8 Hz, 1H), 2.76–2.42 (m, 4H), 1.99–1.88 (m,
1H), 1.60–1.35 (m, 4H), 1.25–1.08 (m, 1H), 0.96 (d,
J = 6.9 Hz, 3H), 0.88 (s, 9H), 0.85 (d, J = 6.9 Hz, 3H), 0.02
(s, 6H); 75 MHz 13C NMR (CDCl3) d 210.2, 159.2, 138.9,
138.7, 130.3, 129.4, 128.3, 127.5, 127.4, 114.9, 113.7, 77.2,
75.5, 73.0, 72.9, 71.3, 68.5, 55.2, 50.1, 48.4, 37.8, 36.6, 32.4,
29.9, 26.1, 18.4, 15.3, 14.3, ꢀ3.7, ꢀ4.1; IR (neat) 3453
(broad), 2931, 1710, 1514, 1250, 1093, 1038, 836,
757 cmꢀ1. Anal. Calcd for C36H56O6Si requires C, 70.55;
H, 9.21. Found: C, 70.36; H, 9.28. Compound 19:
20
Rf = 0.60 (35% EtOAc/hexanes); ½aꢁD ꢀ0.8 (c 1.09,
CHCl3); 300 MHz 1H NMR (CDCl3) d 7.37–7.26 (m,
5H), 5.91–5.79 (m, 1H), 5.06–5.03 (m, 1H), 5.00 (dd,
J = 1.1, 1.1 Hz, 1H), 4.51, (s, 2H), 3.66 (dd, J = 9.1,
4.3 Hz, 1H), 3.49 (dd, J = 9.1, 6.2 Hz, 1H), 3.40 (ddd,
J = 6.9, 4.8, 4.8 Hz, 1H), 3.23–3.21 (m, 1H), 2.37–2.27 (m,
1H), 2.00–1.85 (m, 1H), 1.04 (d, J = 6.7 Hz, 3H), 0.96 (d,
J = 7.0, 3H); 75 MHz 13C NMR (CDCl3) d 142.2, 137.7,
128.4, 127.7, 127.6, 114.0, 78.8, 74.7, 73.5, 40.9, 35.6, 14.4,
13.2; IR (neat) 3487 (broad), 2965, 1455, 1092, 737,
698 cmꢀ1. Anal. Calcd for C15H22O2 requires C, 76.88; H,
9.46. Found: C, 76.66; H, 9.56. Compound 12: Rf = 0.26
20
Rf = 0.64 (25% EtOAc/hexanes); ½aꢁD +7.9 (c 0.1.54,
CHCl3); 300 MHz 1H NMR (CDCl3) d 7.34–7.25 (m,
5H), 5.82 (ddd, J = 16.9, 10.4, 6.1 Hz, 1H), 5.17 (app. dt,
J = 17.1, 1.4 Hz, 1H), 5.08–4.99 (m, 2H), 4.94–4.86 (m,
1H), 4.48 (ABq, JAB = 12.1 Hz, Dv = 9.1 Hz, 2H), 4.13
(ddd, J = 6.1, 6.1, 6.1 Hz, 1H), 3.52 (dd, J = 9.0, 4.6 Hz,
1H), 3.47 (dd, J = 6.4, 2.6 Hz, 1H), 3.28 (dd, J = 9.0,
7.6 Hz, 1H), 2.00 (s, 3H), 1.99 (s, 3H), 1.95–1.32 (m, 9H),
1.20–1.08 (m, 1H), 0.95 (d, J = 7.0 Hz, 3H), 0.90 (s, 9H),
0.87 (s, 9H), 0.83 (d, J = 6.7 Hz, 3H), 0.06 (s, 3H), 0.03 (s,
3H), 0.02 (s, 3H), 0.01 (s, 3H); 75 MHz 13C NMR (CDCl3)
d 170.6, 170.3, 140.5, 138.7, 128.3, 127.4, 114.4, 77.1, 73.1,
73.0, 70.7, 70.1, 67.3, 43.2, 38.8, 37.9, 36.3, 33.0, 30.1, 26.1,
25.8, 21.1, 18.4, 18.2, 15.2, 14.0, ꢀ3.7, ꢀ4.1, ꢀ4.4, ꢀ4.9;
IR (neat) 2931, 1741, 1470, 1363, 1249, 1095, 1027, 837,
775 cmꢀ1. Anal. Calcd for C38H68O7Si2 requires C, 65.85;
H, 9.89. Found: C, 65.80; H, 9.92.
20
(5% EtOAc/hexanes); ½aꢁD +8.0 (c 1.28, CHCl3); 300 MHz
1H NMR (CDCl3) d 7.35–7.25 (m, 5H), 4.90–4.80 (m, 2H),
4.40 (ABq, JAB = 11.9 Hz, Dv = 9.9 Hz, 2H), 3.72–3.62 (m,
1H), 3.56 (dd, J = 8.9, 4.5 Hz, 1H), 3.51 (dd, J = 5.9,
2.1 Hz, 1H), 3.29 (dd, J = 8.2, 8.2 Hz, 1H), 2.24–1.91 (m,
3H), 1.76 (s, 3H), 1.72 (br s, 1H), 1.62–1.37 (m, 4H), 1.24–
1.10 (m, 1H), 0.98 (d, J = 6.9 Hz, 3H), 0.89–0.87 (m, 12H),
0.05 (s, 3H), 0.03 (s, 3H); 75 MHz 13C NMR (CDCl3) d
142.8, 138.8, 128.3, 127.5, 127.4, 113.5, 77.5, 73.1, 72.9,
68.9, 46.1, 37.9, 36.5, 35.4, 30.7, 26.1, 22.4, 18.4, 15.2, 14.3,