Selective synthesis of α-organylthio esters and α-organylthio ketones from β-keto esters and sodiumS-organyl sulfurothioates under basic conditions

Abstract

We described herein a selective method to prepare α-organylthio esters and α-organylthio ketones by the reaction of β-keto esters with sodium S-benzyl sulfurothioate or sodium S-alkyl sulfurothioate (Bunte salts) under basic conditions in toluene as the solvent at 100 °C. When 4 equivalents of a base were used, a series of differently substituted α-thio esters were obtained with up to 90% yield. On the other hand, employing 2 equivalents of a base, α-thio ketones were achieved after 18 h under air. Furthermore, after a shorter reaction time, the isolation of keto–enol tautomers was possible, revealing them as significant intermediates for the mechanism elucidation.

Direct Synthesis of α-Sulfenylated Ketones under Electrochemical Conditions

“…1-(Benzylthio)propan-2-one (3m). 46 This compound was purified using a hexanes/ethyl acetate gradient (9.5:0.5, 9:1, 8.5:1.5) as the eluent. It was obtained as a colorless oil in 40% yield (0.4 mmol, 72 mg).…”

H-Bond Mediated Phase-Transfer Catalysis: Enantioselective Generating of Quaternary Stereogenic Centers in β-Keto Esters

“…Among the possible substrates, β-dicarbonyl compounds, especially β-ketoesters, undoubtedly stand out [18][19][20]. These compounds can undergo numerous organic transformations (including alkylation) to form a quaternary stereogenic center with a variety of substituents, allowing further organic transformations and various post-functionalization processes [21][22][23].…”