Stereoselective reductive radical cyclization of ketonitriles catalyzed by Cp2TiCl2 in the presence of chlorosilane and zinc

Reductive radical cyclization of ketonitriles was catalyzed by Cp2TiCl2 in the presence of Me3SiCl, zinc powder and imidazole, giving the 2-amino-3-cyano-2-cyclopenten-1-ols in moderate to good yields with high trans selectivity (up to 94% trans). The influence of the catalyst, chlorosilane, co-reductant, solvent, and temperature on both the yield and diastereoselectivity of the cyclized products was investigated in detail.