反应详情

A solution of 257.6 g (982 mmol) triphenylphosphine in 1 l methylenechloride was treated with 162.8 g (491 mmol) tetrabromomethane (the reaction was heated up to reflux and was then cooled with an ice bath) and after 40 minutes at room temperature treated with 157.4 ml (1129 mmol) triethylamine (the reaction was heated up to reflux and became dark violet). After cooling (0° C.), 62.7 g (245.5 mmol) of trans-(4-formyl-cyclohexylmethyl)-methyl-carbamic acid tert-butyl ester (example 1.2) in 600 ml methylenechloride were added during 20 minutes. The solution was stirred for 20 hours at room temperature, evaporated and filtered through silica gel (deactivated with hexane/Et3N) with a 99:1 to 4:1 v/v mixture of hexane and ether as eluent to yield 61.5 g (61%) of trans-[4-(2,2-dibromo-vinyl)-cyclohexylmethyl]-methyl-carbamic acid tert-butyl ester as brown oil, MS: 409 (M, 2Br).

1. temperaturewas heated up
2. temperatureto reflux
3. temperaturewas heated up
4. temperatureto reflux
5. additionwere added during 20 minutes
6. customevaporated
7. filtrationfiltered through silica gel (deactivated with hexane/Et3N) with a 99:1 to 4:1 v/v mixture of hexane and ether as eluent