A chiral oxazoline for catalytic enantioselective Nozaki-Hiyama-Kishi allylation and vinylation of aldehydes

Abstract

Asymmetric allylation and vinylation of aldehydes with allyl halides and vinyl halides have been achieved using the chromium(II)-oxazoline catalyst. The catalyst promotes the highly efficient enantioselective Nozaki–Hiyama-Kishi (NHK) allylation of aldehydes using allyl bromide, producing the corresponding homoallylic alcohols in good yields (up to 84%) and a high level of enantioselectivity (up to 98% ee). Meanwhile, the NHK vinylation of aldehydes produce desired allylic alcohols in satisfactory yields (up to 88%) and a high level of enantioselectivity (up to 97% ee). We developed a reliable and milder protocol for preparing chiral homoallylic and allylic alcohols.

Keywords

• Asymmetric allylation
• Asymmetric vinylation
• Oxazoline ligand
• Nozaki–Hiyama-Kishi
• Enantioselectivity