NiCl/CrCl2 Coupling CrCl. DME OH 25°C R R X=L. Br Le CrCl2, DMF Me OH This carbon-carbon bond forming reaction is highly chemoselective Aldehyde carbonyls are selectively attacked even in the presence of other electrophilic groups e.g. Ketones, esters, and nitriles Gives benzylic or allylic alcohols Takai, K; Kimura, K; Kuroda, T; Hiyama, T, Nozaki, H. Tetrahedron Lett. 1983, 24, 5281NiCl2/CrCl2 Coupling Coupling 1 R X + H R' O CrCl2, DMF 25°C R R' OH X=I, Br i.e.1 I Me + H O O CrCl2, DMF 25°C Me OH O •This carbon This carbon-carbon bond forming reaction is carbon bond forming reaction is highly chemoselective highly chemoselective • Aldehyde carbonyls Aldehyde carbonyls are selectively selectively attacked attacked even in the presence even in the presence of other electrophilic groups of other electrophilic groups e.g. Ketones, esters, and nitriles e.g. Ketones, esters, and nitriles •Gives benzylic benzylic or allylic allylic alcohols alcohols 1Takai, K.; Kimura, K.; Kuroda, T.; Hiyama, T.; Nozaki, H. Tetrahedron Lett. 1983, 24, 5281