General and Asymmetric Synthesis of Protected 1,3,5-Triols with Pendant Functional Groups

Abstract

A stereoselective synthesis of enantiomerically pure 1,3,5-triols of any configuration has been developed. These triols carry suitable functional groups at the termini of the chain which should allow for easy and efficient coupling of two building blocks. The silyloxy-Cope rearrangement of syn-aldols was used to prepare a common advanced intermediate for the synthesis of all four stereoisomeric triols. Three synthetic operationsÐan allylboration, an oxidative desilylation, and a conjugate addition reactionÐwere employed to assemble the target molecules. Their terminal double bond may either be cleaved to give the corresponding aldehydes or oxidized to the methyl ketones in a Wacker process to provide access to two subunits for a coupling reaction.

Total Synthesis of Polyrhacitides A and B by Use of an Iterative Strategy for the Stereoselective Synthesis of 1,3-Polyol Arrays

“…Although numerous synthetic methods for the stereoselective assembly of 1,3-diols were developed over the past decades, , strategies that mimick nature’s iterative approach through repetition of a simple sequence have recently attracted renewed interest. In particular, the iterative allylmetalation of aldehydes has found broad use in reagent-controlled sequences that utilize chiral boron or titanium reagents . While an impressive level of stereocontrol is achieved when employing asymmetric allylboration and allyltitanation protocols, the need for stoichiometric amounts of the chiral reagents limits somewhat their use in large-scale applications.…”