Quaternary onium fluorides

Based on the design of chiral quaternary onium bromides and chlorides as chiral phase-transfer catalysts, chiral quaternary onium fluorides [5] and phenoxides [6] have been developed as chiral base catalysts for homogeneous reactions. 

Quaternary onium fluorides, particularly tetraalkylammonium fluorides, have been widely recognized as a convenient, organic-soluble source of naked fluoride ion. Their utiUty in modem organic synthesis, taking advantage of the nucleophilic... 

To reduce the reaction time between diisocyanates and dianhydrides, catalysts such as alkali metal methoxides, or alkali metal fluoride can be optionally combined with a quaternary onium salt. ° However, the addition of catalysts are not advised in the productions of yarns that should exhibit good characteristics. ... 

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