One-pot thiol-free synthetic approach to sulfides, and sulfoxides selectively

Abstract

A facile and efficient thiol-free one-pot method for direct synthesis of sulfides and sulfoxides under green conditions without using any metal catalyst is reported.

Thiol‐Free E‐Selective Approach to Dithiacyclophanes via Ring‐Closing Metathesis

“…To this end, we identified PTA as an effective source of sulfur. A one‐pot method has been developed in our group in which bromides are directly converted to sulfides without converting them first into thiols [22] . Therefore, by exploiting this method, we assembled dithiadiformyl compounds ( 4 and 5 ) by using PTA and 3‐(bromomethyl)benzaldehyde 1 /4‐(bromomethyl)benzaldehyde 2 in MeOH at room temperature for 2 h. Then, potassium carbonate was added to the reaction mixture and stirred for 10 min.…”

“…In view of this aspect, we identified the need for a flexible method to incorporate sulfur atom in cyclophanes without the involvement of thiol precursors. To this end, potassium thioacetate (PTA) was identified as a source for sulfur atom which is a benign option due to its odorless nature and easy to handle circumstances [22] . The dithia precursors were prepared by using PTA.…”

“…To this end, potassium thioacetate (PTA) was identified as a source for sulfur atom which is a benign option due to its odorless nature and easy to handle circumstances. [22] The dithia precursors were prepared by using PTA. Our group has been dedicated towards the preparation of cyclophanes for the last two decades.…”

Selectivity: A Goal for Synthetic Economy

“…However, following the reaction of 230 with potassium thioacetate (PTA) and then allyl bromide to give 231 , Oxone ® was added in water to the same pot, and after monitoring the reaction mixture by thin-layer chromatography and NMR analysis, the selective formation of sulfoxide 232 was observed (Scheme 49 ). 65…”

“…However, following the reaction of 230 with potassium thioacetate (PTA) and then allyl bromide to give 231, Oxone ® was added in water to the same pot, and after monitoring the reaction mixture by thin-layer chromatography and NMR analysis, the selective formation of sulfoxide 232 was observed (Scheme 49). 65 The RCM failed when compound 234a (R = H) was treated with catalysts such as G-I and G-II at room temperature or under reflux conditions. It was reasoned that the unprotected nitrogen atom present in 234a is coordinating with the Grubbs catalyst and preventing the metathetic cycle.…”