Abstract
A new, clean, and efficient protocol is described for the hydrothiolation of terminal alkynes promoted by KF/Al2O3, using glycerol as recyclable solvent. This improved method furnishes selectively the corresponding anti-Markovnikov vinyl sulfides in good to excellent yields starting from terminal alkynes and aliphatic or aromatic thiols. The irradiation with microwaves facilitated the procedure and accelerates the reaction. The catalytic system and the glycerol can be re-used up to four times without previous treatment, and with comparable activity.
Highlights
Vinyl sulfides are present in natural occurring compounds such as griseoviridin and benzylthiocredillidone, with important biological activities.[1,2] The first compound is a type A streptogramin antibiotic, firstly isolated from Streptomyces graminofaciens,[1] while benzylthiocredillidone is a yellow pigment isolated from the brightly red colored sponge Crella spinulata.[2]
But maintaining our focal point, i.e., a cleaner procedure for the hydrothiolation, we decide to expand the studies using of a recyclable solvent
By using glycerol as solvent, benzenethiol 2a reacted with propargyl alcohol 1a to afford the respective adduct 3b in 80% yield after stirring at 90 °C for 2 hours, a 25% increasing in yield, compared with the solvent-free protocol (Table 1, entries 1 and 2)
Summary
Vinyl sulfides are present in natural occurring compounds such as griseoviridin and benzylthiocredillidone, with important biological activities.[1,2] The first compound is a type A streptogramin antibiotic, firstly isolated from Streptomyces graminofaciens,[1] while benzylthiocredillidone is a yellow pigment isolated from the brightly red colored sponge Crella spinulata.[2]. The best yields were obtained when a mixture of the alkyne 1 (1.0 mmol) and the thiol 2 (1.0 mmol) and KF/Al2O3 (40%, 0.08 g) in glycerol (3 mL), was vigorously stirred at 90 °C for 2-6 hours (Method B, Table 1).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
