Rh(II)-Catalyzed Cyclopropanation of Furans and Its Application to the Total Synthesis of Natural Product Derivatives

Rh­(II)-catalyzed enantioselective cyclopropanations of furans, providing access to synthetically useful building blocks, are reported. After screening of 10 Rh­(II) catalysts, Rh2(S-TCPTTL)4 was identified as a highly efficient and selective catalyst (up to 98% ee, TON 88000, and TOF 24/s) for the cyclopropanation of furans. These cyclopropanes were successfully applied to the enantioselective synthesis of novel paraconic acid derivatives.本研究报道了二价铑（Rh(II)）催化的呋喃对映选择性环丙烷化反应，该反应可获得具有合成应用价值的砌块分子。通过对10种二价铑（Rh(II)）催化剂的筛选，最终确定Rh₂(S-TCPTTL)₄为该呋喃环丙烷化反应的高效高选择性催化剂，其最高对映体过量值（enantiomeric excess，ee）可达98%，转化数（Turnover Number，TON）为88000，转化频率（Turnover Frequency，TOF）为24 s⁻¹。所得环丙烷产物可成功应用于新型帕拉康酸衍生物的对映选择性合成。