Synthetic Reactions by Complex Catalysts. IX. Reaction of Thiol with Isocyanide

Abstract

The reaction of a thiol with an isocyanide proceeds in two directions. In the first reaction (course a), the carbon atom of isocyanide with lone-pair electrons is inserted into the sulfur-hydrogen bond of thiol to produce thioformimidate (I). In the second reaction (course b), isothio-cyanate (II) and the alkane (III) from the alkyl group of thiol are formed. The proportion of the participation of two reactions depends upon the alkyl group of thiol and upon the reaction conditions including whether or not a catalyst is employed. Primary thiol prefers course a to course b, whereas tertiary thiol prefers course b. In the reactions at 15°C, the Group IB and IIB metal compounds, e. g., copper compounds, catalyzed the course a reaction preferably. At higher temperatures, e. g. at 100°C, thiol reacts with isocyanide quite rapidly, even in the absence of a catalyst. However, the catalyst effect favoring course a is seen even in the high-temperature reactions. The mechanism of the reaction, especially course b, has been discussed. Syn-anti structures of thioformimidate were also studied by NMR.

Visible-Light-Enabled Construction of Thiocarbamates from Isocyanides, Thiols, and Water at Room Temperature

“…On the basis of the above experimental results and previous reports, ,− a plausible mechanism for this reaction was proposed as shown in Scheme . Initially, the excited state RB* was produced from Rose Bengal under visible-light irradiation .…”

Studies on the Reactivity ofα-Cyano-α-isocyanoalkanoates - Versatile Synthons for the Assembly of Imidazoles

“…As already observed by Schöllkopf and Handke [3] and Saegusa et al [4] [5], thiolates add to the isocyano C-atom, leading to thioimino esters 6, which, in the present case, could also be isolated and characterized as by-products. As opposed to alkoxides, thiolates attack parallel to the isocyanido and the CN C-atom.…”

Studies on the Reactivity of 1-Cyano-1-isocyanoalkylphosphonic Acid Esters

“…Reaction of 2c with ethyl thiolate, generated from EtSH and Et 3 N, yielded the 4H-imidazole 3, which is the product of a nucleophilic attack of thiolate ion on the cyano group and subsequent ring closure with the isocyano C-atom. The formation of a second compound, leading to the thioimino ester by addition of thiolate to the isocyano Catom, 3,7,8 was not observed.…”