Enantioselective sulfonylation using sodium hydrogen sulfite, 4-substituted Hantzsch esters and 1-(arylethynyl)naphthalen-2-ols

Abstract

Synthesis of sulfonyl-containing axially chiral styrenes through a catalytic asymmetric three-component reaction of 4-substituted Hantzsch esters, NaHSO₃ (sodium hydrogen sulfite), and 1-(arylethynyl)naphthalen-2-ols in the presence of a photocatalyst under visible light irradiation is reported. This transformation proceeds through a radical process under mild conditions, leading to axially chiral (S,E)-1-(1-(alkylsulfonyl)-2-arylvinyl)naphthalen-2-ols in good yields with excellent enantioselectivities. During the reaction process, excellent regioselectivity and chemoselectivity were observed as well. Notably, sodium hydrogen sulfite is used as the sulfur dioxide surrogate in this organocatalytic enantioselective radical sulfonylation under photoinduced conditions.