Strategies for Developing New Reactions of Organic Sulfur Compounds Containing Pyridine and Related Heterocycles

Publisher Website
Google Scholar
Abstract
Characteristic properties of organic sulfur compounds containing heteroaromatics and their reactions are described. Applications of these organic sulfur derivatives in organic synthesis, development of several new reactions and their mechanisms are mentioned as follows: 1) simple sulfoxides such as methyl 2-pyridyl sulfoxide are used as efficient phase transfer catalysts in the SN 2 type displacement reactions and alkylations of active methylene compounds, 2) synthetic application of thionc-thiol tautomerism to active esters results in the development of several important reactions, 3) treatment of benzyl 2-pyridyl sulfoxide and several other related compounds with Grignard reagents leads to a new ligand coupling reaction which is initiated by an attack of the Grignard reagent on the sulfinyl sulfur atom to form a sulfurane as an intermediate in which the two ligands can couple with each other, 4) reactions of 2- and 4-sulfinyl or -sulfonyl substituted pyridines with various nucleophiles afford the corresponding ipso-substitution products in high yields. The mechanism for this reaction is either an ionic or a radical path, depending on the substrates and reagents used in the reactions. In the case of 2-substituted pyridines the reaction proceeds via an ionic process, namely, nucleophilic aromatic substitution at the carbon atom attached to the sulfur functional group, while in the 4-substituted derivative the reactions with Grignard reagents presumably proceed via an electron transfer process, namely, a radical pathway.

This publication has 100 references indexed in Scilit: