Heterogeneous Hydrothiolation of Alkynes with Thiols Catalyzed by Diphosphino-Functionalized MCM-41 Anchored Rhodium Complex

Abstract

A novel diphosphino-functionalized MCM-41 anchored rhodium complex [MCM-41-2P-RhCl(PPh 3 )] was conveniently synthesized by the reaction of diphosphinofunctionalized MCM-41 (MCM-41-2P) with RhCl(PPh 3 ) 3 .It was found that this rhodium complex is an efficient catalyst for the hydrothiolation of terminal alkynes with thiols and can be recovered and recycled by a simple filtration of the reaction solution and used for at least ten consecutive trials without any decreases in activity.

The Emergence of Transition‐Metal‐Mediated Hydrothiolation of Unsaturated Carbon–Carbon Bonds: A Mechanistic Outlook

“…have also demonstrated alkyne insertion into the metal hydride intermediate, thereby ruling out a possible competing vinylidene‐based pathway 19d. More recently, supported catalysts based on [RhCl(PR 3 ) 3 ]19f,h or the application into the synthesis of polymers with optical properties19g have been reported. Interestingly, the substitution of a phosphine ligand in [RhCl(PPh 3 ) 3 ] by an N‐heterocyclic carbene increases the stability of the catalytic species whilst slightly diminishing the initial rate 19i…”

Metal Catalysis in Thiolation and Selenation Reactions of Alkynes Leading to Chalcogen-Substituted Alkenes and Dienes

“…MCM‐41‐supported Wilkinson's catalyst afforded an easily recycled catalytic system to obtain linear E ‐vinyl sulfides from aryl thiols and terminal aromatic and aliphatic alkynes under mild reaction conditions (EtOH, 40 °C, 24 h). The catalyst could be separated by simple filtration and was still highly active even after 10 cycles leading to the products in 63–97 % yields . In another work, Yang and Rioux found that depending on the functional groups linked to the polymer support, stereoselectivity of the Rh‐catalyzed reaction can be switched from E to Z .…”

“…The catalyst could be separated by simple filtration and was still highly active even after 10 cycles leadingt ot he products in 63-97% yields. [36] In another work, Yang and Rioux found that depending on the functional groups linked to the polymer support, stereoselectivity of the Rh-catalyzed reactionc an be switched from E to Z. [37] Under optimized conditions using Rh-P-SBA-15 8 as ac atalyst, aw ide range of alkynes and thiols interacted with excellent E-stereoselectivitya nd high yields (Scheme 18).…”

Übergangsmetallvermittelte Hydrothiolierung ungesättigter Kohlenstoff‐Kohlenstoff‐Bindungen: ein mechanistischer Ausblick

“…in Experimenten mit Deuteriummarkierung die Alkin‐Insertion in die Metallhydrid‐Zwischenstufe und schlossen damit einen möglichen konkurrierenden Vinyliden‐Reaktionsweg aus 19d. Vor kurzem wurden [RhCl(PR 3 ) 3 ]19f,h‐Trägerkatalysatoren sowie die Verwendung in der Synthese von Polymeren mit speziellen optischen Eigenschaften19g beschrieben. Interessanterweise erhöht die Substitution eines Phosphanliganden in [RhCl(PPh 3 ) 3 ] durch ein N‐heterocyclisches Carben die Stabilität der katalytischen Spezies bei geringer Abnahme der Anfangsgeschwindigkeit 19i…”