Synthesis of Constrained Raloxifene Analogues by Complementary Use of Friedel−Crafts and Directed Remote Metalation Reactions
作者:Alexey V. Kalinin、Mark A. Reed、Bryan H. Norman、Victor Snieckus
DOI:10.1021/jo034325k
日期:2003.7.1
deprotection to furnish analogue 2a, a new 5,6,6,6-(C(4)S-C(6)-C(6)-C(6)) sulfur-containing heterocycle. Exposure of 25 with excess LDA induced a DreM cyclization delivering the ortho-substituted 5,6,6,6-(C(4)S-C(6)-C(6)-C(6)) heterocylic analogue 26 in 70% yield. Similar treatment of 13c and 27 afforded 30, representing the novel 5,5,6,6-(C(4)S-C(5)-C(6)-C(6)) ring system, which was subjected to Suzuki-Miyaura
雷洛昔芬(1)的新的受限杂环类似物2a,b和3已通过互补的定向远程金属化(DreM)/ Friedel-Crafts环化方法制备。成功地利用了亚苄基-硫代内酯重排来以高收率构建苯并噻吩13a-c。通过络合然后进行三氟甲磺酸酯化作用而导致的13a和13b选择性脱保护,得到18和23,从而使Suzuki-Miyaura与硼烷16进行有效的交叉偶联,得到联芳基19和24。用BCl(3)处理19引起分子内对位Fridel-Crafts环化和伴随的双重脱保护,以提供类似物2a,新的5,6,6,6-(C(4)SC(6)-C(6)-C(6))含硫杂环。过量的LDA暴露于25会诱导DreM环化,从而产生邻位取代的5,6,6,6-(C(4)SC(6)-C(6)-C(6))杂环类似物26的产率为70%。对13c和27的类似处理得到30,代表新颖的5,5,6,6-(C(4)SC(5)-C(6)-C(6))环系统