The iron(III) chloride-mediated 1,4-addition of mercaptans to α,β-unsaturated ketones and esters under solvent free conditions

• Published in: Tetrahedron letters Vol. 47; no. 41; pp. 7375 - 7380
• Main Authors: Chu, Cheng-Ming, Huang, Wan-Ju, Lu, Chaowei, Wu, Pohsi, Liu, Ju-Tsung, Yao, Ching-Fa
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 09.10.2006; Elsevier
• Subjects: 1,4-Addition; Anhydrous iron(III) chloride; Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; Solvent free; α,β-Unsaturated ketones; α,β-Unsaturated ketones; Anhydrous iron(III) chloride; Solvent free; 1,4-Addition; solvent free; THIOLS; anhydrous iron(III) chloride; 1,4-addition; CYCLOALKENONES; alpha,beta-unsaturated ketones; OLEFINS; ALDEHYDES; CATALYST; MICHAEL ADDITION; ALKYL-HALIDES; CONJUGATE ADDITION
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2006.07.151

The 1,4-addition of various thiols to α,β-unsaturated ketones was completed rapidly in the presence of a catalytic amount (2–3 mol %) of anhydrous iron(III) chloride under solvent free conditions and an air atmosphere. Anhydrous iron(III) chloride is more active than that of other ferric salts. With more reactive and/or less steric reagents ( 1a– c and/or 2a– 2c), expeditious conditions (short reaction times at room temperature) could be employed. With less reactive and/or steric reagents ( 1d– g and/or 2d– e), a slight increase in reaction time was required, but high yields were obtained. The FeCl 3 catalyst causes preferential interactions with α,β-unsaturated ketones present in the reaction.