Synthesis of chiral molecules from non-chiral crystals by controlled reaction at a single surface

A procedure is described for performing reactions at a single face of a single crystal of organic compounds, using as examples the cis-dihydroxylation of tiglic and crotonic acids by osmium tetraoxide, and the dibromination of tiglic acid. For molecules whose orientation in the crystalline state is appropriate, reactions carried out in this way can produce enantiomerically enriched products from a non-chiral crystal and reagent. Enantiomeric excesses are dependent upon the crystal quality; values up to 30% have been achieved in the reactions of tiglic acid with osmium tetraoxide or bromine vapour.