Lewis acid-promoted addition of methylenecyclopropanes to aldehydes and ketones

Article abstract of DOI:10.1016/S0040-4039(97)00981-7

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 chiral α- and β-alkoxy aldehydes proceeded with high levels of chelation control.