Organic Synthesis with Sulfur Heterocycles (Thiazoles) as Auxiliaries. The Thiazole Route to Carbohydrates and Biologically Active Derivatives

Abstract

Abstract Functionally-substituted thiazoles at C-2, namely 2-trimethylsilylthiazole (2-TST), 2-thiazolylmethylenetriphenylphosphorane (2-TMP) and 2-thiazolylcarbonitle N-oxide (2-TNO) serve as effective auxiliaries in new synthetic strategies for the stereoselective synthesis (THIAZOLE ROUTE) of long-chain protected polyhydroxyaldehydes, i.e. carbohydrate-like materials, starting from readily available precursors such as chiral hydroxy- and aminoaldehydes. These methodologies are based on two essential operations, both chemically and stereochemically very efficient; i) the coupling between the functionally-substituted thiazole and an appropriate substrate by a carbon-carbon bond forming reaction; ii) the aldehyde release in the resulting adduct by thiazole into formyl conversion. Some compounds obtained in this way are transformed by functional group elaborations into molecules of biological relevance such as deoxy- and aminosugars, and sphingosines.