HSiCl3 mediated synthesis of rivastigmine and miotine

Strategies for preparing chiral molecules in enantiomerically enriched form is a field of very active research. In this context, the use of trichlorosilane in presence of catalytic amount of a chiral Lewis base is a well established methodology to perform enantioselective reduction of C-N bonds1. Trichlorosilane, is a very cheap reducing agent, well inserted into the “green chemistry concept”, is a colorless volatile liquid, supplied by the silicon industry at the price of most organic solvents; moreover the standard reaction workup with aqueous sodium bicarbonate produces innocuous inorganic materials. We plan to use this synthetic methodology in the synthesis of an enantiomerically pure advanced precursor of the blockbuster drug Rivastigmine. We locate the key step of the synthesis in the stereoselective reduction of the C-N double bonds