A. Ethyl 2-(diphenylmethylsilyl)decanoate. A 500-mL, three-necked, round-bottomed flask equipped with a magnetic stirrer, a nitrogen inlet, a 100-mL pressure-equalizing dropping funnel, and a no-air stopper is flame-dried under a vigorous flow of nitrogen, cooled under an atmosphere of nitrogen to −78°C with a dry ice–acetone bath, and charged with 39.2 mL (52.5 mmol) of a 1.34 M solution of butyllithium in hexane (Note 1). To this solution is added 7.4 mL (5.31 g; 52.5 mmol) of diisopropylamine (Note 2) in 7 mL of tetrahydrofuran (Note 3). The resulting solution is warmed to ambient temperature and held for 30 min. The solution is diluted with 50 mL of dry tetrahydrofuran and cooled again to −78°C. To this solution is added 11.6 mL (10.0 g; 50 mmol) of ethyl decanoate (Note 4) in 45 mL of tetrahydrofuran dropwise over a 30-min period. The mixture is kept at −78°C for 30 min to allow the enolate to form, and then 10.3 mL (11.6 g; 50 mmol) of diphenylmethylchlorosilane (Note 5) in 40 mL of tetrahydrofuran is added over a 5-min period. The reaction mixture is allowed to reach ambient temperature and stir at that temperature for 8 hr. It then is cooled to 0°C, diluted with hexane (150 mL), washed with cold water (2 × 100 mL), dried over magnesium sulfate, filtered, and concentrated at reduced pressure (Note 6). The crude product, which is ca. 95% pure (Note 7), is purified by rapid filtration through 50 g of silica gel (Note 8) with 1% ethyl acetate–hexane (Note 9) as eluant. There is obtained 18.4–18.7 g (93–94%) of ethyl 2-(diphenylmethylsilyl)decanoate (Note 10). Similar results are obtained on a larger scale (Note 11).

B. 2-Methyl-2-undecene. A 1-L, three-necked, round-bottomed flask equipped with a magnetic stirrer, a nitrogen inlet, a 500-mL pressure-equalizing dropping funnel, and a no-air stopper is flame-dried under vacuum, cooled to room temperature under an atmosphere of nitrogen, and charged with 87 mL (260 mmol) of 3 M methylmagnesium bromide in ether (Note 12). This solution is cooled to 0°C (ice bath) and 52 g (130 mmol) of ethyl 2-(diphenylmethylsilyl)decanoate in 260 mL of tetrahydrofuran (Note 3) is added over an 8-min period. After the addition is complete, the reaction mixture is warmed to room temperature and heated to reflux for 24 hr. The reaction mixture is again cooled to 0°C and 244 mL (390 mmol) of 1.6 M methyllithium in tetrahydrofuran (Note 13) is added over a 30-min period. After the addition is complete, the reaction mixture is heated to reflux for 24 hr, cooled to 0°C (ice bath), and 29.2 g (260 mmol) of solid potassium tert-butoxide (Note 14) is added in three portions (Note 15). The reaction mixture is heated to reflux for 1 hr, cooled to 0°C, diluted with hexane (100 mL), and hydrolyzed by the dropwise addition of 1 M hydrochloric acid (240 mL), followed by about 150 mL of 3 M hydrochloric acid until a pH of 4 is reached (Note 16). The organic layer is separated and the aqueous layer is extracted with hexane (3 × 100 mL). The combined organic layers are dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure (Note 6) to give 55 g of crude material (Note 17). This material is diluted with 150 mL of dry hexane (Note 18) and applied to a silica gel column (Note 8). The product is obtained by eluting with hexane and collecting 200-mL fractions. This material, which contains small amounts of dimethyldiphenylsilane and diphenylmethylsilanol, is chromatographed under 3–5 psi on a silica gel column (50 × 2.8 cm) eluting with hexane (Note 19) to give 11.3 g (51.8%) of the olefin (Note 20).