Palladium‐Catalyzed Sequential C(sp2)‐H Alkynylation/Annulation of 2‐Phenylphenols with Haloalkynes Using Phenolic Hydroxyl as the Traceless Directing Group

Abstract An efficient, palladium(II)‐catalyzed, C( sp 2 )‐H alkynylation/annulation of 2‐phenylphenols with haloalkynes for the synthesis of substituted 6‐methylene‐6 H ‐dibenzo[ b,d ]pyrans is reported. This protocol features a traceless directing group strategy, unique regioselectivity and mild reaction conditions. Significantly, preliminary mechanistic studies suggest that the sequential C( sp 2 )‐H alkynylation and annulation reaction could be involved in the transformation procedure. magnified image