Palladium-catalyzed aerobic intermolecular cyclization of acrylic acid with 1-octene to afford α-methylene-γ-butyrolactones: the remarkable effect of continuous water removal from the reaction mixture and analysis of the reaction by kinetic, ESI-MS, and XAFS measurements.

Further study of our aerobic intermolecular cyclization of acrylic acid with 1-octene to afford α-methylene-γ-butyrolactones, catalyzed by the Pd(OCOCF(3))(2)/Cu(OAc)(2)⋅H(2)O system, has clarified that the accumulation of water generated from oxygen during the reaction causes deactivation of the Cu cocatalyst. This prevents regeneration of the active Pd catalyst and, thus, has a harmful influence on the progress of the cyclization. As a result, both the substrate conversion and product yield are efficiently improved by continuous removal of water from the reaction mixture.