Stereoselective synthesis of α-bulnesene, 4-epi-α-bulnesene, and 5-epi-α-bulnesene
作者:Edward Piers、Kin Fai Cheng
DOI:10.1139/v70-372
日期:1970.7.15
Lithium-ammonia reduction of the hydroguaiazulene derivative 6, followed by oxidation of the resulting diol 13, gave, in a highly stereoselective manner, the keto alcohol 14. The latter was converted into 5-epi-a-bulnesene (2). In a similar sequence of reactions, 4-epi-a-bulnesene (3) was obtained from compound 9. Photochemical rearrangement of the previously obtained dienone 25 gave the hydroguaiazulene
氢化愈创甘油醚衍生物 6 的锂-氨还原,然后氧化所得二醇 13,以高度立体选择性的方式得到酮醇 14。后者转化为 5-epi-a-bulnesene (2)。在类似的反应序列中,从化合物 9 中获得 4-epi-a-bulnesene (3)。先前获得的二烯酮 25 的光化学重排得到了氢愈创甘油醚衍生物 27。后者依次进行乙酰化、氢化和硼氢化钠还原得到差向异构二醇 31 和 32 的混合物。当该混合物用吡啶中的对甲苯磺酸处理时,所得烯烃二酯 35 依次进行氢化 [三(三苯基膦) 氯铑] 和氢化铝锂还原,结晶得到二醇37。