Poly -tartrate synthesis

The asymmetric epoxidation of functionalized alkenes still attracts considerable attention. Synthetic chemists continue to be in search of new and improved routes to epoxides, since they provide versatile intermediates for natural product synthesis. The topic of preparative techniques for chiral epoxides is seldom broached without the mention of the Sharpless epoxidation. Indeed, the impact of this protocol cannot be overestimated, as new applications continue to be reported. For example, linear poly(tartrate ester) ligands have been used this past year to generate a solid-supported Sharpless-type catalyst <97CC123>. 

Investigation of template poly condensation kinetics has only been studied within a very narrow scope. Polymerization of dimethyl tartrate with hexamethylene diamine was found to be enhanced by using as a template poly(vinyl pyrrolidone), poly(2-vinyl pyridine), or polysaccharides and poly(vinyl alcohol), poly(4-vinyl pyridine). In this case, the template can be treated as a catalyst. No information exists on the influence of the template on the order of reaction. The increase in molecular weight of the polymerization product by the template can be induced by a shift of equilibrium or by an increase in the reaction rate. A similar increase in the reaction rate was observed when poly(4-vi-nyl pyridine) was used in the synthesis of poly(terephtalamides) activated by triphenyl phosphite.The authors suggested that a high molecular weight template was involved in the increase of the local concentration of the substrate (terephthalic acid) by adsorption and activation via N-phosphonium salt of poly(4- vinyl pyridine). 

The synthesis of polytartaramides was first reported by Minoura and coworkers.79 During the 1970s, Ogata et a .80-81 described the polycondensation of tartaric acid itself or its 2,3-69-methylene derivative with diamines, by a variety of procedures. These authors also studied the copolymerizations of diethyl-L-tartrate with other diesters64 and reported that the rate of polymerization of dimethyl-L-tartrate with 1,6-diaminohexane in dimethyl sulfoxide at 60°C increased when the reactions were conducted in the presence of such polymer matrices as poly (vinyl pyrrolidone), pullulan, and poly (vinyl alcohol). The rate increased with increasing molecular weight of the matrix.82... 

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