Cyclization of Active Methylene Isocyanides with α-Oxodithioesters Induced by Base: An Expedient Synthesis of 4-Methylthio/Ethoxycarbonyl-5-acylthiazoles

Cyclization of tosylmethyl isocyanide with α-oxodithioesters in the presence of KOH is reported for the synthesis of 4-methylthio-5-acylthiazoles. Similarly, ethyl isocyanoacetate underwent cyclization with α-oxodithioesters to form 4-ethoxycarbonyl-5-acylthiazoles in the presence of DBU/EtOH. Mechanisms for the formation of thiazoles are proposed. These thiazoles can also be obtained by Takeda reaction, in which thiazole-4,5-anhydride is acylated with aromatic compounds followed by esterification; however, that approach requires two steps and suffers from the formation of a regioisomeric mixture of products.

Copper-mediated direct sulfonylation of C(sp2)–H bonds employing TosMIC as a sulfonyl source

Cu-Mediated sulfonylation of C(sp2)–H bonds with p-tosylmethyl isocyanide (TosMIC) as a sulfonyl source was developed utilizing a removable N,O-directing group.

Improvement of the Van Leusen reaction in the presence of β-cyclodextrin: a green and efficient synthesis of oxazoles in water

An efficient approach for the synthesis of oxazoles through the Van Leusen reaction in the presence of β-cyclodextrin is described. In aqueous medium using β-cyclodextrin as a supramolecular catalyst, tosylmethyl isocyanide was deprotonated by triethylamine and subsequently underwent an addition/cyclization reaction with aldehydes to produce corresponding oxazoles in excellent yields. This protocol improves the Van Leusen reaction with the use of catalytic amounts of base at low temperature in green media.