合成路线图解说明: Chromanone (II) was prepared by reaction of 2',5'-dihydroxyacetophenone (I) with acetone and pyrrolidine. Alkylation of the hydroxyl group of (II) with 4,4,4-trifluorobutyl bromide in the presence of NaH provided ether (III). The keto group of (III) was then reduced to alcohol (IV), which was subsequently dehydrated to chomene (V) by means of p-toluenesulfonic acid in hot toluene. Asymmetric epoxidation of (V) with NaOCl employing the chiral auxiliary (R,R)-bis(3,5-di-tert-butylsalicylidene)-1,2-diaminocyclohexane manganese (III) chloride furnished epoxide (VI). Finally, epoxide opening by the sodium salt of N-methyl methanesulfonamide afforded the title compound. |