R_2Si=P-SiR_2F: 1,3-Sigmatropic Migration of Fluorine in a 2-Phospha-1,3-disilaallyl Derivative Capable of Conjugation and Its Conversion to Phosphadisilacyclopropanes

摘要

Although stable compounds with isolated Si=E bonds (E = C, Si, N, P, As, S), which have an enormous synthetic potential at their disposal, have been prepared and even structurally characterized over the last few years, only very little is known aboutheteronuclear conjugated Si—E pi systems, and nothing is known about corresponding homonuclear Si—Si pi systems. Until now. only the 1,3-diphospha- and l,3-diaza-2-silaallyl anionic derivatives A and B have been experimentally studied. We have been investigating the synthesis of stable conjugated Si—P pi systems C (allyl, butadiene, and benzene analogues), whose stepwise formation can be achieved with salt-condensation reactions, as, 101 example, in the preparation of phosphasilenes (Si=P compounds).