This invention relates to processes for the preparation of antiparasitic isoxazoline compounds enriched in an enantiomer using quinine-based chiral phase transfer catalyst. The invention also relates to novel quinine-based phase transfer catalysts and to a toluene solvent form of the isoxazoline compound of the invention.本發明係關於使用基於奎寧之對掌性相轉移催化劑製備富集於對映異構體中之抗寄生異㗁唑啉化合物之方法。本發明亦關於新穎的基於奎寧之相轉移催化劑及本發明之異㗁唑啉化合物之甲苯溶劑形式。