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温度

0 °C

To a stirred, cooled (-78° C., dry ice/acetone) solution of nonyltriphenylphosphonium bromide (prepared as described in Example 1 Part A) (12.09 g, 22 mM, 1.2 eq.) in dry THF (125 ml) was added dropwise under argon a 2.5M solution of n-BuLi in hexane (7.32 ml, 18.3 mM, 1 eq.). Twenty minutes after completed addition HMPA (19 ml, 110 mM, 6 eq.) was added followed by dropwise addition of the title A aldehyde (3.0 g, 183 mM) in 25 ml of THF over a 1.5 hour period. The mixture was warmed to 0° C. (ice bath) over a 30 minute period, then added to 200 ml of H2O and extracted (2×) with ethyl acetate. The organic phase was washed with saturated NH4Cl, dried over anhydrous Na2SO4 and evaporated to a thick brown oil. Crude oil was flash chromatographed on LPS-1 silica gel eluting with (8:2) Hex-CH2Cl2. Product containing fractions were evaporated to give 1.65 g (33%) of the desired title Wittig product (mixture of cis and trans isomers obtained) as a clear oil with consistent NMR (CDCl3, 60 MHz) spectral data. TLC (1:1) EtOAc-Hex, Rf product=0.80, UV and PMA, single spot.

1. customprepared
2. customTwenty minutes
3. additionwas added
4. extractionextracted (2×) with ethyl acetate
5. washThe organic phase was washed with saturated NH4Cl
6. dry with materialdried over anhydrous Na2SO4
7. customevaporated to a thick brown oil
8. customchromatographed on LPS-1 silica gel eluting with (8:2) Hex-CH2Cl2
9. additionProduct containing fractions
10. customwere evaporated
11. customto give 1.65 g (33%) of the desired title
12. additionWittig product (mixture of cis and trans isomers obtained) as a clear oil with consistent NMR (CDCl3, 60 MHz) spectral data