作者:Sameshnee Govender、Edwin M. Mmutlane、Willem A. L. van Otterlo、Charles B. de Koning
DOI:10.1039/b707187f
日期:——
Readily available 2,2′,6,6′-tetramethoxy-1,1′-biphenyl was transformed in 14 synthetic steps into the natural product cardinalin 3 using a bidirectional approach. One of the key steps was the formation of the cis-1,3-dimethylnaphtho[2,3-c]pyran ring. (±)-1,1′-[6,6′-Diallyl-5,5′-bis(benzyloxy)-1,1′,3,3′-tetramethoxy-2,2′-binaphthalene-7,7′-diyl]diethanol was treated with O2 in the presence of CuCl2 and catalytic PdCl2 to afford 5,5′-bis(benzyloxy)-7,7′,9,9′-tetramethoxy-1,1′,3,3′-tetramethyl-1H,1′H-8,8′-bibenzo[g]isochromene. Hydrogenation of this compound afforded 7,7′,9,9′-tetramethoxy-cis-1,3-cis-1′,3′-tetramethyl-3,3′,4,4′-tetrahydro-1H,1′H-8,8′-bibenzo[g]isochromene-5,5′-diol in quantitative yield, which was converted in 3 steps to cardinalin 3.
现成的2,2′,6,6′-四甲氧基-1,1′-联苯通过双向合成法在14个合成步骤中转化为天然产物卡达林(cardinalin 3)。其中一个关键步骤是形成顺式-1,3-二甲基萘[2,3-c]吡喃环。(±)-1,1′-[6,6′-二烯丙基-5,5′-双(苄氧基)-1,1′,3,3′-四甲氧基-2,2′-萘-7,7′-二基]二乙醇在CuCl2和催化剂PdCl2的存在下,与O2反应,生成了5,5′-双(苄氧基)-7,7′,9,9′-四甲氧基-1,1′,3,3′-四甲基-1H,1′H-8,8′-二苯并[g]异喹啉。这化合物经过氢化反应,定量产率得到7,7′,9,9′-四甲氧基-顺式-1,3-顺式-1′,3′-四甲基-3,3′,4,4′-四氢-1H,1′H-8,8′-二苯并[g]异喹啉-5,5′-二醇,随后在3个步骤中转化为卡达林(cardinalin 3)。