J. Org. Chem. 1989,54,5819-5821 6 7.59 (dd, J = 16.5, 11 Hz, 1 H), 7.10-7.53 (m, 9 H), 6.94 (b d, J = 10.05 Hz, 1 H), 6.81 (b d, J = 16.5 Hz, 1 H), 6.54 (ddd, J = 16.5, 10.5, 1 Hz, 1 H), 5.70 (b d, J = 16.5 Hz, 1 H), 5.17 (d, J = 10.5 Hz, 1H) ppm; 13CNMR (CDC13,75 MHz) 6 140.68 (d) 137.09 (d), 136.95 (s),136.80 (d), 136.44 (s), 132.15 (s), 128.83 (d), 128.63 (d), 128.25(d), 127.46 (d), 126.91 (d), 126.21(d), 125.39 (d), 117.48 (t) ppm. (lE,3E)-l-Phenyl-4-(phenylthi0)-1,3,5-hexatriene (7k) was prepared on a 0.50-mmol scale from tram-cinnamaldehyde in 83% yield. The triene was found to be unstable and polymerized on standing at room temperature and was not fully characterized: Rf0.25 (1% ether/petroleum ether);'H NMR (CDCl,, 300 MHz) 6 7.18-7.46 (m, 11H), 6.99 (dd, J = 16.5, 10.5 Hz, 1H), 6.58-6.98 (m, 2 H), 7.75 (d, J = 16.5 Hz, 1 H), 5.33 (dt, J = 10.5, 1.5 Hz, 1 H) ppm; 13C NMR (CDCl,, 75 MHz) 6 136.87 (s), 136.48 (d), 135.50 (s),135.16 (d), 132.72(s), 130.53 (d), 129.70 (d), 128.90 (d), 128.65 (d), 128.09 (d), 126.67 (d), 126.34 (d), 123.30 (d), 118.99 (t) ppm. Reaction of Aldehyde (8) with Allylborane (4). Prepa1,j-octadiene ration of (E)-5-Acetoxy-8-azido-3-(phenylthio)(9). To the allene 3 (260 mg of 94% pure material, 3.9 mmol, neat) was added 9-BBN (7.8 mL of 0.5 M solution in THF, 3.9 mmol). After stirring at 35 "C for 2 h, the mixture was cooled to 25 "C, and a solution of 2-acetoxy-5-azidopentanal(8)22(650 mg, 3.5 mmol) in THF (1mL) was added slowly. After 2 h, 4 N sodium hydroxide (10 drops) was added, and stirring was continued for another 2 h. A small aliquot (ca. 0.2 mL) was removed, and the solvent was evaporated. 'H NMR spectroscopy showed only the E isomer of 9 to the limits of detection of our 300-MHz instrument. The reaction mixture was then diluted with pentane (8 mL) and washed with brine (3 x 3 mL). The organic layer was dried (Na2S04)and concentrated in vacuo, and the residue was purified by flash chromatography (30:l hexane/ethyl acetate) to give 1.04 g (93%)of 9, which was found to be a >97:
