Enantioselective Mercuriocyclization of γ-Hydroxy-cis-alkenes

Abstract
Asymmetric mercuriocyclization of gamma-hydroxy-(Z)-alkenes has been achieved using Hg(II) complexed with tartrate-derived 4-(2-naphthyl)bisoxazoline as chiral ligand to give rise to 2-monosubstituted tetrahydrofurans in 86-95% ee. Not only the linker connecting two oxazolines but also their 4-substituents were found crucial for high enantioselectivity. In addition, tuning the ketal protecting group of tartrate as well as adding MeOH and K(2)CO(3) worked beneficially.