Grignard Reagent‐Mediated Regioselective 1,8‐Addition of α‐(2‐Thienylidene)‐β‐ketosulfones

• Published in: Advanced synthesis & catalysis Vol. 365; no. 13; pp. 2264 - 2270
• Main Authors: Chang, Meng‐Yang, Chen, Kuan‐Ting, Chen, Hsing‐Yin
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 04.07.2023; Wiley Subscription Services, Inc
• Subjects: Addition; Bromides; Chemistry; Chemistry, Applied; Chemistry, Organic; Cosolvent; C−H Functionalization; Diethyl ether; Physical Sciences; Reagents; Regioselectity; Regioselectivity; Science & Technology; Solvents; Transition metals; β-Ketosulfone; SCHLENK EQUILIBRIUM; Addition; Cosolvent; 1,6-CONJUGATE ADDITION; beta-Ketosulfone; ASYMMETRIC CONJUGATE ADDITION; ORGANOCATALYTIC 1,6-ADDITION; C-H Functionalization; DIVERGENT SYNTHESIS; PARA-QUINONE METHIDES; Regioselectity; SOLVENT
• ISSN: 1615-4150; 1615-4169
• DOI: 10.1002/adsc.202300227

Grignard reagent‐mediated and solvent‐controlled regioselective 1,8‐addition of α‐(2‐thienylidene)‐β‐ketosulfones provides diversified substituted 2‐thienylmethyl β‐ketosulfones in moderate yields in a diethyl ether–dioxane cosolvent and dioxane (v/v=4/1) under ice‐bath conditions. The 1,4‐addition of α‐heterocyclic β‐ketosulfones was also studied. The structure of the key product was confirmed via X‐ray analysis. The uses of various reaction solvents and organomagnesium bromides were investigated for transition metal‐free C−H functionalization. Related plausible mechanisms are proposed and discussed. The DFT calculations are utilized to rationalize the regioselectivity of the 1,8‐addition reaction.