New synthetic route to (S)-(−)-equol through allylic substitution
作者:Yuji Takashima、Yuichi Kobayashi
DOI:10.1016/j.tetlet.2008.06.085
日期:2008.8
Allylic substitution of allylic picolinate 5 with a copper reagent derived from p-MeOC6H4MgBr (6) and CuBr·Me2S produced the anti SN2′ product 7 with high regioselectivity and efficient chirality transfer. Oxidative cleavage of the olefinic function to the alcohol followed by bromination afforded bromide 16, which upon demethylation and intramolecularether ring formation furnished (S)-(−)-equol (3)
用衍生自p -MeOC 6 H 4 MgBr(6)和CuBr·Me 2 S的铜试剂对烯丙基吡啶甲酸5进行烯丙基取代,得到具有高区域选择性和有效手性转移的抗S N 2'产物7。烯烃官能团被氧化裂解为醇,然后溴化,得到溴化物16,该溴化物在脱甲基和形成分子内醚环后提供(S)-(-)-牛尿酚(3)。
Synthetic access to optically active isoflavans by using allylic substitution
作者:Yuji Takashima、Yuki Kaneko、Yuichi Kobayashi
DOI:10.1016/j.tet.2009.10.116
日期:2010.1
A general approach to the (S)- and (R)-isoflavans was invented, and efficiency of the method was demonstrated by the synthesis of (S)-equol ((S)-3), (R)-sativan ((R)-4), and (R)-vestitol ((R)-5). The key step is the allylic substitution of (S)-6a (Ar1=2,4-(MeO)2C6H3) and (R)-6b (Ar1=2,4-(BnO)2C6H3) with copper reagents derived from CuBr·Me2S and Ar2-MgBr (7a, Ar2=4-MeOC6H4; 7b, 2,4-(MeO)2C6H3; 7c,
发明了(S)-和(R)-异黄酮的通用方法,并且该方法的效率通过合成(S)-雌马酚((S)-3),(R)-sativan((R)-4),和(R)-vestitol((R)-5)。关键的步骤是(的烯丙基取代小号) - 6a中(AR 1 = 2,4-(MEO)2 C ^ 6 ħ 3)和(- [R )-图6b(AR 1 = 2,4-(BNO)2 Ç6 H 3)和衍生自CuBr·Me 2 S和Ar 2 -MgBr(7a,Ar 2 = 4-MeOC 6 H 4 ; 7b,2,4-(MeO)2 C 6 H 3 ; 7c,2的铜试剂-momo -4- MeOC 6 ħ 3),家具抗小号ñ 2的产品([R )-图8a和(小号) - 8b中,ç93-97%的手性转移,收率为60-75%。产物的烯烃部分被氧化裂解,然后除去Ar 1部分上的Me和Bn基团。最后,用K 2 CO 3和Mitsunobu试剂对溴化苯酚