Department of Chemistry and Biochemistry, Colorado College , Colorado Springs, Colorado 80903-3243, United States.
Loker Hydrocarbon Research Institute and Department of Chemistry, University of Southern California , Los Angeles, California 90089-1661, United States.
Org Lett. 2015 Dec 18;17(24):6170-3. doi: 10.1021/acs.orglett.5b03172. Epub 2015 Dec 4.
An efficient microwave-assisted protocol for the synthesis of 2-/3-methylthiochroman-4-ones by superacid-catalyzed alkylation followed by cyclic acylation (cyclization via intramolecular acylation) is described. Using easily accessible benzenethiols and crotonic acid/methacrylic acid with triflic acid (as catalyst of choice for needed optimal acidity), the reaction was tuned toward the formation of the cyclized products in good selectivity and yield. A mechanism involving the formation of carbenium-carboxonium superelectrophilic species is suggested.
描述了一种通过超酸催化的烷基化反应和随后的环酰化反应（通过分子内酰化进行环化）高效合成 2-/3-甲基硫代色满-4-酮的微波辅助方法。使用易得的苯硫酚和巴豆酸/甲基丙烯酸与三氟磺酸（作为所需最佳酸度的催化剂），该反应以良好的选择性和收率形成了环状产物。提出了一种涉及碳阳离子-羧鎓超亲电物种形成的机制。
