STEREOSELECTIVE FUNCTIONALIZATION AT C-9 OF RETINAL : SYNTHESIS OF 9-TRANS-19-NOR-9-HALORETINAL ANALOGS

Abstract

Stereoselective functionalization at C-9 of retinal based on the use of the C₄+X-unit is described. A sequential linkage of C₄+X-units (X=Cl, Br, and I) with ylide 8 (C₁₀) and phosphonate 12 (C₅)selectively gave 9-trans-19-nor-9-Cl, Br, and I-retinal derivatives.