Phosphine-Catalyzed Asymmetric (3+2) Annulations of δ-Acetoxy Allenoates with 2-Naphthols.

Phosphine-catalyzed (3+2) annulations of δ-acetoxy allenoates with 2-naphthols are reported, wherein the δC of allentoate reacts with the αC of 2-naphthol to form the C-C bond while a C-O bond is formed between the γC of allenoate and the hydroxyl group of 2-naphthol. When (R)-SITCP is used as the catalyst, 1,2-dihydronaphtho[2,1-b]furans are obtained in moderate to good yields and with high enantioselectivity. This method is useful for the construction of enantiomerically enriched atropoisomeric furans via a central to axial chirality conversion strategy.