ASYMMETRIC-SYNTHESIS OF CDP840 BY JACOBSEN EPOXIDATION - AN UNUSUAL SYN SELECTIVE REDUCTION OF AN EPOXIDE

An asymmetric synthesis of the PDE IV inhibitor, CDP840 (3) is reporte d. The absolute stereochemistry was controlled by a Jacobsen epoxidati on of the Z triaryl olefin 8 (89% ee) or the E triaryl olefin 9 (48% e e). The disparate results in stereocontrol were interpreted in terms o f the ''skewed side-on approach model'' proposed by Jacobsen. LiBK4 . BH3 reduction of the epoxides was found to proceed with retention of c onfiguration.