Urea derivative organocatalyzed enantioselective Friedel–Crafts alkylation of α‐naphthols with isatins

Abstract

An organocatalytic enantioselective Friedel–Crafts alkylation of α‐naphthols with isatin derivatives was catalyzed by Takemoto‐type urea catalyst to give optical active 3‐(naphthalen‐2‐yl)‐3‐hydroxy‐2‐oxindoles in 75%–92% yields with up to 95% enantiomeric excess (ee) value. The catalyst type and the substrate scope were broadened in this methodology.

Recent Advances in Asymmetric Addition Reactions to Isatins

“…57 In 2022, Jin disclosed that Takemoto-type urea catalyst C14 could serve as an efficient activator for both isatins 1 and α-naphthols 62 through concerted activation, thus promoting Si-face addition to produce an array of 3-aryl-3hydroxyl-2-oxindoles 63 in high yields with good to outstanding enantioselectivity (Scheme 24a). 58 Similar thiourea catalyst C15 exhibited higher catalytic performance, since less reactive phenol 64 and 4-chloroisatin 1c could also be successfully applied (Scheme 24b). 59 Scheme 24 Asymmetric Friedel-Crafts reaction of naphthols and phenols with isatins 7 Asymmetric Annulations of Isatins…”