Methods are provided for synthesis of abscisic acid and 8' analogues thereof (including an enantiopure 8'-acetylene analogue) including methods wherein the previously reported first step of oxidation of 2,6-dimethylphenol (VI) to 2,6- dimethylbenzoquinone, mono ketal (VII) is replaced by a novel two step process comprising (i) oxidation of 2,6-dimethylphenol (VI) using potassium peroxymonosulfate with a catalytic amount of iodobenzene to produce 2,6- dimethylbenzoquinone (XVI) and (ii) ketalization of 2,6-dimethylbenzoquinone (XVI) using ethylene glycol, trimethylorthoformate with a catalytic amount of p- toluenesulfonic acid to produce 2,6- dimethylbenzoquinone, mono ketal (VII).
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