High-Pressure Diels−Alder Cycloadditions between Benzylideneacetones and 1,3-Butadienes: Application to the Synthesis of (<i>R,R</i>)-(−)- and (<i>S,S</i>)-(+)-Δ<sup>8</sup>-Tetrahydrocannabinol
combination with the mild Lewis acid HfCl4·2THF allows these reactions to efficiently and regioselectively produce a series of ortho-substituted cyclohexenyl-benzene cycloadducts, that are useful precursors for the expeditious construction of the privileged 6,6-dimethyltetrahydro-6H-benzo[c]chromene skeleton. Application to the synthesis of Δ8-trans-THC in both enantiomericpure forms is based on the successful
据报道,各种烷氧基/烷基取代的亚苄基丙酮与甲基-1,3-丁二烯的高压Diels-Alder反应。高压(8-11 kbar)与温和的路易斯酸HfCl 4 ·2THF结合活化使这些反应有效和区域选择性地产生了一系列邻位取代的环己烯基-苯环加合物,它们对于快速构建环己烯基有用的前体。特权的6,6-二甲基四氢-6 H-苯并[ c ]亚甲基骨架。到Δ的合成应用8 -反式-THC在两种对映体纯的形式是基于由SAMP -腙的方法选择环加成的成功解决。