反应详情

To a 0.2M solution of the tertiary alcohol of Step 4 in CH2Cl2 were added 5 equiv. of dihydropyran and 0.1 equiv. of triphenylphosphonium bromide and the mixture was stirred at reflux for 1 day. Then, the same amount of dihydropyran and triphenylphosphonium bromide were added and the mixture stirred at reflux another day. Toluene was added and the resulting solution was filtered through silica with EtOAc:toluene 0:100 to 2:98 to afford the title product.

1. temperatureat reflux for 1 day
2. stirringthe mixture stirred
3. temperatureat reflux another day
4. filtrationthe resulting solution was filtered through silica with EtOAc:toluene 0:100 to 2:98