Bouchet Damien, Van Elslande Elsa, Masson Géraldine
Institut de Chimie des Substances Naturelles (ICSN), CNRS UPR 2301, Université Paris-Saclay, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette, France.
HitCat, Seqens-CNRS joint laboratory, Seqens'Lab, 8 Rue de Rouen, 78440 Porcheville, France.
Org Lett. 2023 Jul 21;25(28):5395-5399. doi: 10.1021/acs.orglett.3c02011. Epub 2023 Jul 10.
A highly enantioselective formal (4 + 2)-cycloaddition between carboxylic acids and thiochalcones promoted by (+)-HBTM-2.1 isothiourea organocatalyst has been reported. The methodology relied on the generation of 1-ammonium enolate intermediates and proceeded through a nucleophilic 1,4-addition-thiolactonization cascade. It enabled the stereocontrolled preparation of sulfur-containing δ-thiolactones in good yields, moderate diastereoselectivity, and excellent enantiomeric excess (up to 99%). This annulation benefited from the peculiar reactivity of uncommon electron-rich thiochalcones used as Michael acceptors.
据报道，(+)-HBTM-2.1异硫脲有机催化剂可促进羧酸与硫代查耳酮之间的高度对映选择性形式(4 + 2)环加成反应。该方法依赖于1-铵烯醇盐中间体的生成，并通过亲核1,4-加成-硫内酯化级联反应进行。它能够以良好的产率、适度的非对映选择性和优异的对映体过量(高达99%)立体控制制备含硫δ-硫内酯。这种环化反应受益于用作迈克尔受体的不常见富电子硫代查耳酮的特殊反应性。
