80 mL of THF was added to a solution of titanium (IV) chloride (15.6 mL, 141.8 mmol, 15.0 equivalent) and CH₂Cl₂ (600 mL) while stirring in a 2-L round-bottomed flask at 0°C under argon. The resulting golden yellow solution was allowed to stir for 10 minutes at 0°C.

Afterwards, 135.0 mL of TMEDA (907.3 mmol, 96.0 equivalent) was added dropwise, changing the color to brown. This solution was allowed to stir at room temperature for 30 minutes. After stirring, activated zinc (22.2 g, 340.2 mmol, 36.0 equivalent) and lead (II) chloride (5.3 g, 18.9 mmol, 2.0 equivalent) were added to the solution in one portion. This caused the color to change again, resulting in a blue-green mixture.

Next, olefin 16 (6.2g, 9.5 mmol, 1.0 equivalent) and 1,1-dibromoethane (13.8 mL, 151.2 mmol, 16.0 equiv) in 150 mL of CH₂Cl₂ was added dropwise via an addition funnel for 20 minutes. 10 mL of CH₂Cl₂ was used to rinse the addition funnel three times (the rinsing solution was added to the round-bottomed flask).

The solution was then heated under reflux for 2 hours, cooled to 0°C, and quenched with 110 mL of saturated aqueous potassium carbonate solution. It was stirred for 30 minutes (at 0°C) and filtered using a 3 cm alumina pad. CH₂Cl₂ (3 × 300 mL) was used to wash the round-bottomed flask three times and the solution was filtered. The filtrate was concentrated under reduced pressure, and the precipitate was filtered and washed with 500 mL of solvent (50% EtOAc/hexanes).

Flash column chromatography was used to purify the product (10 × 10 cm silica gel column, eluting with 10% EtOAc/hexanes) and 125-mL fractions were collected. Fractions 3-18 were found to contain product and were combined and concentrated under reduced pressure to give cyclic enol ether 17 (4.7 g, 80%), a clear yellow oil.

R_f = 0.39 (5 % EtOAc/toluene); [α]20D = +37.9 (c = 1.0, CHCl3); 500 MHz ¹H NMR (CDCl3) δ 7.38-7.23 (m, 7H), 6.88-6.84 (m, 2H), 5.75 (ddd, J = 15.6, 1.5, 1.5 Hz, 1H), 5.52 (ddd, J = 15.6, 5.4, 5.4 Hz, 1H), 4.85 (d, J = 6.8 Hz, 1H), 4.82 (d, J = 7.3 Hz, 1H), 4.69-4.60 (m, 3H), 4.55 (dd, J = 4.4, 2.9 Hz, 1H), 4.52 (d, J = 10.7 Hz, 1H), 4.14 (dd, J = 5.4, 1.5 Hz, 2H), 4.01 (dddd, J = 9.8, 9.8, 2.0, 2.0 Hz, 1H), 3.95 (dq, J = 6.4, 6.4 Hz, 1H), 3.83 (ddd, J = 10.7, 5.4, 2.5 Hz, 1H), 3.80 (s, 3H), 2.08 (dddd, J = 17.1, 9.8, 6.8, 2.9 Hz, 1H), 2.02-1.84 (m, 1H), 1.80 (ddd, J = 14.2, 10.3, 2.0 Hz, 1H), 1.75 (ddd, J = 13.7, 6.8, 3.4 Hz, 1H), 1.61 (ddd, J = 13.2, 10.7, 2.4 Hz, 1H), 1.36-1.25 (m, 1H), 1.20 (d, J = 6.4 Hz, 3H), 1.17 (s, 6H), 0.90 (s, 9H), 0.05 (s, 6H); 125 MHz ¹³C NMR (CDCl3) δ 159.3, 159.1, 138.7, 138.1, 131.1, 129.6, 128.6, 128.0, 127.8, 125.9, 114.0, 93.6, 93.2, 78.0, 74.1, 73.6, 71.6, 69.6, 64.6, 55.4, 40.5, 36.4, 28.4, 26.2, 26.1, 26.0, 20.6, 18.6, 15.8, -4.8; 125 MHz DEPT 13C NMR (CDCl3) CH3 δ 55.4, 26.2, 26.1, 25.9, 15.8, -4.8; CH2 δ 93.6, 73.6, 69.5, 64.6, 36.4, 28.3, 20.6; CH1 δ 138.7, 129.6, 128.6, 128.0, 127.8, 125.9, 114.0, 93.2, 78.0, 74.1, 71.7; CH0 δ 159.3, 159.1, 138.1, 131.1, 40.5, 18.6; IR (neat) 2930, 2856, 1661, 1581, 1462, 1381, 1249, 1098, 1042, 837, 776 cm 1; HRMS (ESI/APCI) calcd for C₃₇H₅₆NaO₆Si (M+Na): 647.3744, found: 647.3750.

"Column Chromatography." Wikipedia, the Free Encyclopedia. Web. 14 Apr. 2011. <http://en.wikipedia.org/wiki/Column_chromatography>.

Keck, Gary E., Yam B. Poudel, Thomas J. Cummings, Arnab Rudra, and Jonathan A. Covel. "Supporting Information to Accompany: Total Synthesis of Bryostatin 1." Journal of the American Chemical Society 133 (2011): S2.

"Reflux." Wikipedia, the Free Encyclopedia. Web. 14 Apr. 2011. <http://en.wikipedia.org/wiki/Reflux>.