(4S)-p-Hydroxybenzyl-1,3-oxazolidin-2-one as a solid-supported chiral auxiliary in asymmetric 1,3-dipolar cycloadditions

Evansʹ chiral auxiliary was grafted onto both Merrifield and Wang resins and, after functionalisation, they were used as chiral dipolarophiles in a 1,3-dipolar cycloaddition involving both a nitrile oxide and a nitrone. The cycloadducts were cleaved and analysed by chiral HPLC: the recovered supported chiral oxazolidinone was functionalised and reused in further cycloadditions. The stereochemical results as well as the possibility of recycling the chiral linker supports the applicability of solid-supported chiral auxiliaries.