Syntheses of bicyclic 1,2-diols via the ring-expansion of bridgehead aldehydes of bicyclo[3.2.1]octane and bicyclononanes with benzoyl triflate
作者:Ken'ichi Takeuchi、Keizo Ikai、Masayasu Yoshida、Akio Tsugeno
DOI:10.1016/s0040-4020(01)81430-7
日期:——
chromatography, have been converted to the corresponding diols, and their structures determined. For synthetic purposes, 11a gives bicyclo[3.3.1]nonane-1,endo-2-diol (27), and 12a the endo and exo isomers of bicyclo[4.3.1]decane-1,2-diol (33 and 35, respectively). From 13a is furnished bicyclo[4.2.2]decane-1,2-diol (42). Diols 27, 33. and 42 are conveniently oxidized to the corresponding ketols by using silver
双环[3.2。]辛烷(11a),双环[3.3.1]壬烷(12a)和双环[3.2.2]壬烷(13a)的桥头醛已通过使用苯甲酰基三氟甲磺酸酯(三氟甲磺酸-最后)得到两种或三种在桥头碳上含有羟基的双环1,2-二醇单苯甲酸酯的混合物。对照实验表明,该反应是动力学控制的。通过比较由对应于所产生的二醇单苯甲酸酯的母体烃的分子力学计算出的应变能,发现环的扩展方向是可预测的。通过结晶或柱色谱法易于以实际收率分离出的主要单苯甲酸酯已转化为相应的二醇,并确定了它们的结构。出于合成目的,11a给出双环[3.3。1] nonane-1,endo-2-diol(27)和12a是双环[4.3.1]癸烷-1,2-二醇的内和外异构体(分别为33和35)。从13a中提供双环[4.2.2]癸烷-1,2-二醇(42)。使用碳酸银可以50-80%的收率方便地将二元醇27、33和42氧化为相应的酮醇。在相似的条件下,二醇35氧化为1-羟基双环[4