Preparation of optically active allethrolone
AssigneeRoussel Uclaf
InventorsJacques Martel, Jean Tessier, Jean-Pierre Demoute
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Abstract
A novel process for the preparation of (R) or (S) 2-allyl-3-methyl-4-hydroxy-2-cyclopentene-1-one comprising reacting a boron halide with an ester of a chiral carboxylic acid of the formula ##STR1## where A is organic group of a chiral carboxylic acid and (R) or (S) 2-allyl-3-methyl-4-hydroxy-2-cyclopentene-1-one and treating the reaction mixture with water to obtain allethrolone with the same configuration of the starting ester in high yields without undesired by-products produced in known methods.
Claims12
A process for the preparation of (R) or (S) allethrolone comprising reacting at least two moles of a boron halide with one mole of an ester of a chiral carboxylic acid of the formula ##STR6## where A is the organic group of a chiral carboxylic acid and (R) or (S) 2-allyl-3-methyl-4-hydroxy-2-cyclopentene-1-one at -40.degree. to 0.degree. C. in an organic solvent and treating the reaction mixture with water to obtain allethrolone with the same configuration of the starting ester.
Dependencies are inferred from the claim text.