One‐Pot Synthesis of Fused Tetrahydroquinoline‐Iminosugar Derivatives

An efficient and simple one-pot synthesis of structurally diverse novel tetrahydroquinoline-fused iminosugars was developed through the aza-Diels-Alder mechanism. The adaptability of this method has been demonstrated by a variety of imines and d/l-ribose tosylates, and both, electron-donating and -withdrawing substituted imines proceed well. In addition, this reaction is characterized by simple operation, good yield, and high atom economy. Some synthetic iminosugars showed moderate anti proliferation of HCT116 tumor cells. Under the catalysis of Yb(OTf)3, the cyclization of iminium-ion intermediates and imines was promoted through the aza-Diels-Alder mechanism, providing a simple reaction for the synthesis of tetrahydroquinoline-iminosugars derivatives with good stereoselectivity. The absolute structures of compounds 1 a and 5 a were confirmed by single crystal X-ray diffraction and 2D NMR.image