The mass spectral fragmentation of 2,2′‐bis‐trimethylsilylbenzhydrylethers. An indication for transannular hydrogen/deuterium rearrangements and transannular elimination reactions

The mass spectra of the methyl‐, trideuteromethyl‐, ethyl‐ and pentadeuteroethylethers of 2,2′‐bis‐trimethylsilylbenzhydrol are reported. The most significant ions arise from the [M – CH3]+ ion, formed by loss of a methyl radical from one of the trimethylsilyl groups. After ring formation by interaction of the siliconium ion centre with an aromatic nucleus, the ion loses (CH3)3SiOR (R = CH3, C2H5, CD3 and C2D5), giving ion m/e 223. The fragment (CH3)3SiOCH3 is also eliminated in the four ethers investigated from the ion [M – R]+. Attack of the siliconium ion. Indications are found for a transannular hydrogen/deuterium rearrangement and a transannular elimination reaction. The intensity of some peaks in the spectra are discussed in relation to group R.