Polyols structural configuration

Although the absolute configuration has only been established for a few polyene macrolide antibiotics, the search for new, efficient, and selective strategies for the synthesis of their polyol structures is in full swing. A number of the synthetic procedures presented here will certainly be used in future syntheses of this class of natural products [19]. 

The reactions of boric acid solutions with diols have been used for almost a century to examine structural differences among carbohydrates. The complexity of these reactions seems to arise not only from simple structural differences but also from differences in carbohydrate configuration and conformation. The precise nature of these reactions is not clear. Recent studies of the chemistry of polyol-boric acid solutions have clarified some aspects of these reactions that have important bearing on the structure of carbohydrates in solution. Nevertheless, some of the most fundamental questions about the nature of the reaction are still unanswered. 

In 1901, von Lippmann reported the discovery of an optically active tetrahydroxycyclohexane in beet sugar molasses. This polyol, which von Lippmann named betitol, has not been investigated further and, since it does not appear to be identical with any of the other known tetra-hydroxycyclohexanes, both its structure and configuration are still wholly unknown. 

Reactive Injection Molding. Reactive injection molding (RIM), also known as liquid injection molding (LIM), is a process in which a mixture of two or more reactive materials is injected into a mold where the materials react to form a thermoset structure. Advantages include low cost, low pressure requirements, and flexibility in mold configuration. Conventional systems, such as isocyanate with polyol to produce a polyurethane, release little or no volatiles. The generation of substantial volatiles in the mold is obviously undesirable and has... 

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