Experimental
That's easy, class! It follows a simple recipe!
You first dissolve compound 5 (628 mg, 1.23 mmol) and rhodium(II) acetate dimer (5.5 mg, 0.0123 mmol) in 12 mL anhydrous benzene at room temperature. You then immediately immerse the mixture in a preheated, 80ºC oil bath and reflux it for 120 min. (Be careful, it's hot!) After completion of the reaction and subsequent cooling to room temperature, you remove the solvent under vacuum and purify the residue by flash column chromatography (EtOAc/hexane = 1/1) to afford compound 4 as a white solid (360 mg, 60% yield)!
Your characterization data should look like this:
- Compound 4:
- Rf = 0.31 (silica gel, EtOAc/hexanes = 1/1)
- 1H-NMR (500 MHz, CDCl3): δ 7.14-7.10 (m, 2H), 6.99 (t, J = 7.7 Hz, 1H), 5.75-5.72 (m, 1H), 5.56 (d, J = 13.2 Hz, 1H), 5.22 (d, J = 10.1 Hz, 1H), 5.13 (d, J = 4.8 Hz, 1H), 5.10 (d, J = 4.8 Hz, 1H), 4.84 (d, J = 18.6 Hz, 1H), 4.75 (s, 1H), 4.36-4.26 (m, 4H), 3.83 (d, J = 13.2 Hz, 1H), 3.70 (s, 3H), 2.93 (d, J = 18.0 Hz, 1H), 2.31 (d, J = 6.3 Hz, 1H), 2.27 (s, 3H), 1.38 (t, J = 7.1 Hz, 6H), 1.08 (s, 3H), 0.25 (s, 3H)
- 13C-NMR (125 MHz, CDCl3): d 169.4, 169.3, 155.9, 134.3, 131.9, 131.8, 131.1, 127.4, 124.4, 120.8, 99.7, 90.14, 90.07, 76.6, 75.1, 73.2, 63.43, 63.38, 62.85, 62.80, 57.5, 47.1, 38.2, 27.6, 27.2, 25.6, 18.7, 16.55, 16.50, 16.45
- HRMS-ESI Calcd for C24H36O8P [M + H+]: 483.2148. Found: 483.2136
Full speed ahead!
Gong, J.; Lin, G.; Sun, W.; Li, C.-C.; Yang, Z. J. Am. Chem. Soc. 2010, 132, 16745–16746.