反应详情

温度

-78 °C

A solution of (S)-3-tert. butoxy-2-methyl-1-propylmagnesium bromide was prepared from 3.34 g. (0.016 mole) of the S-(+)- 3-tert. butoxy-2-methyl-1-bromopropane and 0.42 g. (0.0176 mole) of magnesium powder in a total of 14 ml. of dry tetrahydrofuran as described in Example 4. To a stirring solution of 2 g. (6.4 moles) of (R)-(+)-3,7-dimethyl-1-octyl p-toluenesulfonate in 6 ml. of dry tetrahydrofuran cooled to -78° C. was added 7 ml. (~8 mmoles) of this Grignard solution dropwise followed by 033 ml. of a 0.1 M Li2CuCl4 solution in dry tetrahydrofuran. The resulting mixture was stirred at -78° C. for 10 minutes then in an ice bath (0°-5° C) for 2 hours and finally at room temperature for 16.5 hours. The reaction mixture was treated with 1 N aqueous H2SO4 and the product was isolated by extraction with ether in the manner of Example 1. Chromatography of the crude product (1.7 g.) on silica gel (50 parts) afforded pure (2R,6R)-(+)-1-tert. butoxy-2,6,10-trimethylundecane (eluted with 49:1 parts by volume hexane-ether). Evaporative distillation gave 1.19 g. (68.8%) of (2R,6R)-(+)-1tert. butoxy-2,6,10-trimethylundecane as a colorless oil, b.p. 75°-80° C. (bath temperature) (0.05 mm Hg.); [α]25D + 1.29°(c 2.01, hexane).

1. additionwas added 7 ml
2. waitin an ice bath (0°-5° C) for 2 hours
3. waitfinally at room temperature for 16.5 hours