Control of remote stereochemistry using phosphine oxides: formal synthesis of any stereoisomer diol (RR, RS, SR or SS) bearing 1,5-related stereogenic centres across an E double bond

Abstract

γ-Alkenyl β-hydroxy phosphine oxides have been epoxidised stereoselectively to give γ,δ-epoxy β-hydroxy phosphine oxides with high anti stereoselectivity. The γ-anisyl or γ-furyl ring of γ-aryl β-hydroxy phosphine oxides have been cleaved oxidatively to reveal a carboxylic acid and a ketone respectively. In the latter case, the ketone was reduced highly stereoselectively to give (4R*,5S*,6R*)-8-benzyloxy-6-diphenylphosphinoyloctane-1,4,5-triol as a single diastereoisomer with three controlled stereogenic centres. This method was then applied to the synthesis of three of the diastereoisomers of 8-benzyloxy-6-diphenylphosphinoyldodecane-1,4,5-triol with four controlled stereogenic centres; the middle two stereogenic centres were removed using an E-selective Horner–Wittig elimination to give either diastereoisomer of 8-benzyloxydodec-5-ene-1,4-diol with 1,5-related stereogenic centres across an E alkene.