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Helvetica Chimica Acta – Vol. 94 (2011)
and brine (15 ml), dried (anh. Na2SO4), and concentrated in vacuo. The crude product was purified by
CC to afford aldehyde as a colorless liquid (1.08 g, 76%).
To a stirred soln. of TiCl4 (0.01 ml, 0.12 mmol) in CH2Cl2 (5 ml) was added dried Ti(OiPr)4 (0.102 ml,
0.22 mmol) at 08 under N2. The soln. was allowed to warm to r.t. After 1 h, Ag2O (0.05 g, 0.24 mmol) was
added at r.t., and the mixture was stirred for 5 h under exclusion of direct light. The mixture was diluted
with CH2Cl2 (10 ml) and treated with (S)-binaphthol (0.14 g, 0.49 mmol) at r.t. for 2 h to furnish chiral
bis[Ti(IV)oxide] (S,S)-I. The in situ generated (S,S)-I catalyst was cooled to ꢀ 158 and treated
sequentially with the above prepared aldehyde (1.08 g 2.43 mmol) in CH2Cl2 (50 ml) and allyl(tribu-
tyl)tin (1.06 g, 3.16 mmol) at ꢀ 158. The whole mixture was allowed to warm to 08 and stirred for 16 h.
The reaction was quenched with sat. NaHCO3 (10 ml), and the mixture was extracted with Et2O
(100 ml). The org. extracts were dried (Na2SO4). Evaporation of solvents and purification of the residue
by CC afforded 8 (0.94 g, 74%). Colorless liquid. IR (neat): 3386, 3028, 2921, 2852, 1674, 1634, 1406, 1268,
1
1191, 1048. H-NMR (200 MHz, CDCl3): 7.76 – 7.63 (m, 5 H); 7.53 – 7.32 (m, 7 H); 7.24 – 7.08 (m, 3 H);
5.83 – 5.66 (m, 3 H); 5.18 – 5.06 (m, 2 H); 4.32 – 4.28 (m, 1 H); 3.83 – 3.79 (m, 1 H); 2.58 – 2.20 (m, 4 H);
1.99 – 1.51 (m, 2 H); 1.12 (s, 9 H). 13C-NMR (50 MHz, CDCl3): 142.0; 134.1; 132.3; 130.2; 130.0; 129.8;
129.5; 129.3; 128.4; 128.2; 126.0; 115.8; 75.5; 74.1; 42.5; 41.2; 40.5; 31.7; 25.8; 19.5. ESI-MS: 485 ([M þ
H]þ).
(4S,6E)-8-{[(tert-Butyl)(diphenyl)silyl]oxy}-10-phenyldeca-1,6-dien-4-yl Prop-2-enoate (9). To a
stirred soln. of 8 (0.94 g, 1.94 mmol) in CH2Cl2 (30 ml) was added acryloyl chloride (0.26 g, 2.92 mmol)
and Et3N (0.39 g, 3.89 mmol) at 08. The mixture was allowed to warm to r.t., and stirred for 4 h. The
mixture was diluted with H2O (10 ml) and extracted with CH2Cl2 (4 ꢁ 10 ml). The combined org. layer
was dried (Na2SO4), and the solvent was removed under vacuum to obtain the crude residue, which was
purified by CC to afford pure 9 (1.51 g, 78%). Colorless oil. IR (neat): 3028, 2921, 2852, 1724, 1675, 1633,
1407, 1269, 1190, 1049. 1H-NMR (200 MHz, CDCl3): 7.75 – 7.60 (m, 5 H); 7.50 – 7.32 (m, 7 H); 7.24 – 7.08
(m, 3 H); 6.41 – 6.39 (m, 1 H); 6.22 – 6.00 (m, 2 H); 5.92 – 5.85 (m, 4 H); 5.17 – 5.06 (m, 3 H); 4.50 – 4.48
(m, 1 H); 4.02 – 4.0 (m, 1 H); 2.66 – 2.36 (m, 6 H); 1.96 – 1.66 (m, 2 H); 1.12 (s, 9 H). ESI-MS: 539 ([M þ
H]þ).
(4S,6E)-8-Hydroxy-10-phenyldeca-1,6-dien-4-yl Prop-2-enoate (10). To a soln. of 9 (0.80 g,
1.48 mmol) in dry THF (10 ml) was added TBAF (1.48 ml, 1.48 mmol, 1m soln. in THF) dropwise at
08, and the mixture was stirred for 1 h. H2O (20 ml) was added, and the mixture was extracted with
AcOEt (50 ml). The org. extracts were washed with brine (30 ml) and dried (Na2SO4). Evaporation of
the solvent afforded 10 (0.35 g, 80%). Colorless liquid. IR (neat): 3429, 3028, 2921, 2852, 1723, 1674, 1634,
1406, 1268, 1191, 1048. 1H-NMR (200 MHz, CDCl3): 7.37 – 7.15 (m, 5 H); 6.76 – 6.72 (m, 1 H); 6.39 (dd,
J ¼ 17.3, 1.5, 1 H); 6.18 – 6.02 (m, 2 H); 5.87 – 5.67 (m, 2 H); 5.16 – 5.04 (m, 2 H); 4.46 – 4.44 (m, 1 H);
4.11 – 4.07 (m, 1 H); 2.71 – 2.57 (m, 2 H); 2.48 – 2.39 (m, 2 H); 2.30 – 2.23 (m, 2 H); 1.88 – 1.69 (m, 2 H).
13C-NMR (50 MHz, CDCl3): 166.4; 140.9; 131.8; 129.6; 126.9; 124.4; 116.3; 77.1; 71.9; 39.9; 37.8; 32.2;
29.0. ESI-MS: 301 ([M þ H]þ).
(4S,6E)-8-Oxo-10-phenyldeca-1,6-dien-4-yl Prop-2-enoate (2). To a stirred soln. of 10 (0.35 g,
0.66 mmol) in dry CH2Cl2 (15 ml), DessꢀMartin periodinane (0.40 g, 0.972 mmol) was added at 08 and
the mixture was stirred for 4 h at r.t. The reaction was quenched with sat. NaHCO3 soln./hypo soln.
¼Na2S2O3 soln. (1:1; 15 ml) and stirred for 30 min and then extracted with CH2Cl2 (2 ꢁ 20 ml). The
combined org. layers were washed with H2O (10 ml), dried (anh. Na2SO4), and concentrated. The crude
residue was purified by CC to afford pure (0.26 g, 77%). Viscous liquid. IR (neat): 3429, 3028, 2921, 2852,
1723, 1674, 1634, 1406, 1268, 1191, 1048. 1H-NMR (200 MHz, CDCl3): 7.32 – 7.26 (m, 3 H); 7.21 – 7.18 (m,
2 H); 6.77 – 6.71 (m, 1 H); 6.39 (dd, J ¼ 17.2, 1.4, 1 H); 6.17 – 6.04 (m, 2 H); 5.83 (dd, J ¼ 10.2, 1.2, 1 H);
5.76 – 5.72 (m, 1 H); 5.14 – 5.06 (m, 2 H); 4.56 – 4.50 (m, 1 H); 2.97 – 2.82 (m, 4 H); 2.56 – 2.47 (m, 2 H);
2.37 (t, J ¼ 6.6, 2 H). 13C-NMR (50 MHz, CDCl3): 199.1; 165.5; 141.6; 132.8; 132.7; 131.1; 128.5; 128.3;
126.1; 118.5; 71.7; 41.7; 38.1; 36.5; 30.0; 29.7. ESI-MS: 321 ([M þ Na]þ).
(6R)-6-[(2E)-4-Oxo-6-phenylhex-2-en-1-yl]-5,6-dihydro-2H-pyran-2-one (1) [3]. To a stirred soln.
of benzylidine[1,3-bis(2,4,6-trimethylphenyl)imidazolidin-2-ylidene]dichloro(tricyclohexylphosphine)-
ruthenium (Grubbsꢃ 2nd-generation catalyst; 8 mg, 5 mol-%) in CH2Cl2 (40 ml) at 558 was added to 2
(0.26 g, 0.07 mmol) dissolved in CH2Cl2 (10 ml). The resulting mixture was stirred for 6 h, after which
time all of the starting material had been consumed (TLC). The solvent was removed under reduced