Synthesis of SB 222618. A potential PDE IV inhibitor

PDE IV inhibitor SB 222618 was prepared by regioselective SN2′ addition of 9 to bromoallene 6a followed by a stereoselective borane reduction of 4 to afford 2 which by a palladium mediated coupling with 3, delivered SB 222618 (1) in good yield.