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    Catalyst-Tuned Electrophilic Chlorination of Diverse Aromatic Compounds with Sulfuryl Chloride and Regioselective Chlorination of Phenols with Organocatalysts
    (Amer Chemical Soc, 2022) Erturk, Erkan; Yesil, Tolga A.
    In this work, we demonstrate that diverse aromatic compounds can be selectively chlorinated through the fine-tuning of the reactivity of sulfuryl chloride (SO2Cl2) by organocatalysts. Acetonitrile has been identified to activate SO2Cl2 most strongly, thus enabling even chlorination of p-xylene with high yields. 1,4-Dioxane effects chlorination of oxidation-labile aromatic compounds such as p-cresol and 2-naphthol with high yields, 95% and 85%, respectively. An array of potential catalysts has been screened for ortho- and para-selective chlorination of phenols. Thus, we found that acetonitrile, (S)-BINAPO (5 mol %), and diisopropyl ether (4.00 equiv) can catalyze the chlorination of phenols in a para-selective manner (with <= 4:96 o:p ratio), whereas Nagasawa's bis-thiourea (1 mol %), phenyl boronic acid (5 mol %), and (S)-diphenylprolinol (1 mol %) exhibit high ortho selectivity [with <= 99:1 o:p ratio by (S)-diphenylprolinol].
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    Öğe
    Resolution of trans-2-azidocycloalkanols by separation of their mandelic acid esters
    (Pergamon-Elsevier Science Ltd, 2023) Yesil, Tolga A.; Yavuz, Mustafa; Erturk, Erkan
    It is presented that resolution of (+/-)-trans-2-azidocylohexanol and (+/-)-trans-2-azidocyclooctanol can be effected with (R)-mandelic acid. (R)-Mandelate esters of these azido alcohols can be separated by column chromatog-raphy on silica gel in an efficient manner. Upon methanolysis (transesterification) of the diastereomerically pure (R)-mandelate esters by K2CO3, enantiomerically pure trans-2-azidocylohexanols and trans-2-azidocyclooctanols are obtained. Their synthetic relevance has been also demonstrated by subjecting them to some enantiospecific transformations, such as the Mitsunobu reaction and hydrogenolysis of the azide functionality. Notably, this is the first study reporting the preparation of enantiopure trans-2-azidocyclooctanols.