Conjugate Addition of Grignard Reagents to Thiochromones Catalyzed by Copper Salts: A Unified Approach to Both 2-Alkylthiochroman-4-One and Thioflavanone.

Autor: Bellinger TJ; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Harvin T; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Pickens-Flynn T; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Austin N; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Whitaker SH; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Tang Yuk Tutein MLC; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Hukins DT; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Deese N; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA., Guo F; Department of Chemistry, Winston Salem State University, 601 S. Martin Luther King Jr. Dr., Winston Salem, NC 27110, USA.; Biomedical Research Infrastructure Center, Winston Salem State University, Winston Salem, NC 27110, USA.
Jazyk: angličtina
Zdroj: Molecules (Basel, Switzerland) [Molecules] 2020 May 01; Vol. 25 (9). Date of Electronic Publication: 2020 May 01.
DOI: 10.3390/molecules25092128
Abstrakt: Grignard reagents undergo conjugate addition to thiochromones catalyzed by copper salts to afford 2-substituted-thiochroman-4-ones, both 2-alkylthiochroman-4-ones and thioflavanones (2-arylthiochroman-4-ones), in good yields with trimethylsilyl chloride (TMSCl) as an additive. The best yields of 1,4-adducts can be attained with CuCN∙2LiCl as the copper source. Excellent yields of 2-alkyl-substituted thiochroman-4-ones and thioflavanones (2-aryl substituted) are attained with a broad range of Grignard reagents. This approach works well with both alkyl and aromatic Grignard reagents, thus providing a unified synthetic approach to privileged 2-substituted thiochroman-4-ones and a potential valuable precursor for further synthetic applications towards many pharmaceutically active molecules. The use of commercially available and/or readily prepared Grignard reagents will expedite the synthesis of a large library of both 2-alkyl substituted thiochroman-4-ones and thioflavanones for additional synthetic applications.
Databáze: MEDLINE
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