Diastereoselective Aldol Addition Using Boron Trichloride or Alkoxydichloroborane

Article abstract of DOI:10.1002/hlca.19860690309

Under carefully controlled conditions, boron trichloride or alkoxytrichloroborane/ethyldiisopropylamine in CH2Cl2 can be used to effect diastereoselective aldol additions of ethyl ketones to saturated, α,β-unsaturated, or aromatic aldehydes.The C-C bond formation takes place with relative topicity ul ('syn' configuration of the aldols), in selectivities ranging from 90 to 99percent ds (Tables 1-3).Mechanistic aspects of the reaction are discussed.