Cross-coupling of Aryl Sulfides Powered by <i><b>N</b></i>-Heterocyclic Carbene Ligands

Abstract

Cross coupling reactions of aryl sul des are more dif cult than they look. We have disclosed that transition metal NHC complexes allow us to ef ciently use a wide range of aryl sul des as electrophilic coupling partners in various cross coupling reactions and have thus signi cantly expanded the scope of aryl suldes available for the cross coupling technology. Newly introduced nucleophilic partners include arylzinc reagents, Grignard reagents such as alkynylmagnesium species, amines, ketimines, and diborons to achieve Negishi type coupling, Kumada Tamao Corriu type coupling, Buchwald Hartwig type amination, Buchwald Hartwig Miura type carbonyl α arylation, and Miyaura type borylation, respectively. These cross coupling reactions are particularly advantageous when combined with sulfur speci c transformations to prepare organosulfur substrates. Through the development of catalytic transformations of C S bonds, sulfur based organic synthesis has come to complement conventional halogen based organic methodology.

Palladium‐Catalyzed Insertion of Isocyanides into the C−S Bonds of Heteroaryl Sulfides

“…In line with our interest in catalytic C−S bond transformations,,– we herein report that simple insertion of tert ‐butyl isocyanide into the C−S bonds of heteroaryl sulfides proceeded by means of a palladium catalyst to provide thioimidates (Scheme e). The resulting thioimidates could be easily converted into the corresponding thioesters by acidic hydrolysis.…”

Cascades of Interrupted Pummerer Reaction‐Sigmatropic Rearrangement

“…For instance, palladium‐catalyzed arylation of 20 l with various arylzinc iodide‐lithium chloride complexes led to the facile and efficient construction of a library of 2‐aryl‐3‐trifluoromethylnaphthofurans 24 (Scheme ) . A palladium complex Pd‐PEPPSI‐IPr bearing an N‐heterocyclic carbene (NHC) ligand proved to be the effective precatalyst for the arylation, while the conventional phosphine ligands worked sluggishly in some cases. The library consists of new naphthofuran‐based fluorescent molecules that emit in the solid state as well as in solution.…”

“…On one hand, we are interested in developing new methods to synthesize sulfur‐containing compounds by utilizing the fascinating reactivity of organosulfurs. On the other hand, we have been establishing transition‐metal‐catalyzed transformations of carbon‐sulfur bonds as if sulfur moieties serve as efficiently as halogen leaving groups by overcoming the poisonous nature toward transition metal catalysts . By pursuing the couple of approaches alongside, we are aiming at expanding the utility of organosulfur compounds and then creating new sulfur‐based organic synthesis that can complement and/or be beyond the conventional halogen‐based organic synthesis.…”

Nickel(II)/N‐Heterocyclic Carbene Catalyzed Desulfinylative Arylation by C−S Cleavage of Aryl Sulfoxides with Phenylboronic Acids

“…Thioesters, thioalkynes, and sulfonyl chlorides were also applied to react with boronic acids to construct C−C bonds . The earlier progress in the metal‐catalyzed C−S activation and application of organosulfur compounds as electrophilic reagents in C−C formation reactions were summarized . In 2013, Willis and Shi et al.…”