反应详情

The racemic acetate substrate was prepared by one of two methods. The diol route began with racemic 1,2-dihydroxy-3-butene which could be prepared by reacting EpB with water under neutral conditions or with acid catalysis. The diol was treated with p-toluenesulfonyl chloride (p-TsCl) in pyridine at 4° C. to afford the desired monotosylate contaminated with about 10% of the corresponding ditosylate. The monotosylate could be selectively crystallized to afford pure monotosylate in 61% yield. Hydroxytosylate was acetylated under normal conditions (Ac20, Et3N, CH2C12) to provide the acetoxy-tosylate (the desired racemic acetate) in 93% yield. The diol route is illustrated as follows: ##STR3##

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