Sila crown ethers, modified sila crown compounds, their preparation, and their use as phase transfer catalysts

摘要

Organosilicon compounds termed sila crown ethers or "sila crown compounds" have the general formula <IMAGE> in which R<1> and R<2> are organic radicals or hydrogen and n is an integer between 4 and 10 inclusive. Modified sila crown ethers of the general formula <IMAGE> in which R<1> and R<2> are organic radicals, hydrogen or groups which actively support the complexing of metal cations, n is an integer between 3 and 10 inclusive and R<3> is hydrogen or lower alkyl, are prepared. These sila crown ethers and modified sila crown ethers are prepared by reacting polyalkylene glycols with substituted silanes under conditions which favour cyclisation as opposed to polymerisation. The sila crown coumpounds and modified sila crown compounds can be used for the formation of cation complexes and for enhancing anionic reactions, in particular in phase transfer reactions, either in the form of a solution or immobilised on silicon-containing supports.