Highly Stereoselective Synthesis of Functionalised Sinomenine Derivatives by Reducing the C-6 (Ring C)

Sinomenine ether derivatives at C-4 (ring A) were reduced by LiAlH 4 at the C-6 (ring C) to provide the corresponding hydroxyl derivatives with highly stereoselectivity. The desired products were obtained in excellent yields and fully characterised by 1 H NMR, 13 C NMR, MS spectra, elemental analysis and X-ray diffraction. The mild reaction conditions, readily available sinomenine ether derivatives, simple operation and high stereoselectivity make such a reaction highly attractive.