Solvents effect on stereochemistry

Table V compiles the ZIE product isomer ratios of reactions from Table I for which such information has been reported. With 0.5-2% cross-linked polystyrene supptxis, the isomer ratios are similar to those obtained from Wittig reactions in solution. The exceptions appear to be the reactions on more highly cross-linked supports shown in Table IV. There is a clear trend toward greater E selectivity as the degree of cross-linking of the polymer increases. This probably should be explained as an environmental effect, but comparison with solvent effects on stereochemistry of Wittig reactions in the literature reveals no tendency for aromatic solvents, structurally similar to polystyrene, to increase E selectivity.

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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