用3当量的t -BuLi处理苄基2-卤代苯基醚会同时导致锂卤交换和在苄基亚甲基上的锂化。这些二价阴离子不进行维蒂希重排,并且可以被亲电试剂捕获。它们与羧酸酯的反应提供相应的2-芳基-3-羟基-2,3-二氢苯并[ b ]呋喃,为非对映异构体的混合物。随后的酸催化或介导的脱水使各种2-芳基-3-取代的苯并[ b ]呋喃具有中等至良好的总收率。
Copper/P(<i>t</i>
Bu)<sub>3</sub>
-Mediated Regiospecific Synthesis of Fused Furans and Naphthofurans
作者:Togati Naveen、Arghya Deb、Debabrata Maiti
DOI:10.1002/anie.201609401
日期:2017.1.19
to construct substituted fused furans and naphthofurans from readily available starting materials under mild reaction conditions. The utility of the method is further demonstrated by the synthesis of chiral furans from (R)‐(−)‐carvone and (S)‐(+)‐carvone. A plausible mechanism involving the oxidative radical cyclization has been suggested based on experimental observations.
A new method for synthesis of benzofurans and naphthofurans from 2-hydroxystilbene derivatives via an intermolecular cyclization is reported in this study with up to 94% isolated yield.