Enantioselective Alkyne Addition to Aliphatic, Aromatic, and Vinyl Aldehydes Using Zn, iPrI, H8BINOL, and Ti(OiPr)4

Article abstract of DOI:10.1021/acs.joc.5b02185

A new catalytic system based on the readily available Zn, ⁱPrI, H₈BINOL, and Ti(OⁱPr)₄ has been developed which avoids the use of pyrophoric ZnEt₂. It can effectively catalyze the reaction of various terminal alkynes with aromatic, aliphatic, and vinyl aldehydes to generate chiral propargylic alcohols at room temperature with up to 98% yield and 98% enantiomeric excess. This new system signifciantly expands the substrate scope of the previously reported system using Zn, EtI, BINOL, and Ti(OⁱPr)₄.