ChemInform Abstract: 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 reported. The absolute stereochemistry was controlled by a Jacobsen epoxidation of the Z triaryl olefin 8 (89% ee) or the E triaryl olefin 9 (48% ee). The disparate results in stereocontrol were interpreted in terms of the "skewed side-on approach model" proposed by Jacobsen. LiBK4 . BH3 reduction of the epoxides was found to proceed with retention of configuration.