In the presence of a chiral iridium complex, commercially available 3-chloro-2-chloromethyl-1-propene (1) was selectively activated for various reductivecouplings. Depending on the reaction conditions it allows a selective mono- or bidirectional condensation with one or two external aldehydes with excellent enantiocontrol (>90% ee). This approach occurring simply under mild conditions and avoiding
In the presence of TiCl4, methylenecyclopropane (1a) easily reacted with aliphatic aldehydes to give the β-(chloromethyl)allylated products 2 in good yields along with a small amount of the methylenetetrahydrofurans 3. The reaction with chiralα- and β-alkoxyaldehydes proceeded with high levels of chelation control.