Mass Spectra of Spiroorthocarbonates and Their Sulfur Analogues

Abstract

Eleven derivatives of orthocarbonate, spiroorthocarbonates and their sulfur analogues were synthesized to obtain their mass spectra. The molecular ion peaks were clearly observed for the spiro derivatives (eight samples) but hardly detected for the non-spiro derivatives (three samples). The sulfur analogues of the spiroorthocarbonates had much larger relative intensities of the molecular ions than the corresponding spiroorthocarbonates. Molecular ion peaks for aromatic spiroorthocarbonate and its sulfur analogue were observed as the base peaks. Fragmentation of the spiro derivatives was considered to proceed competitively via two of the three major pathways (Scheme 9) depending on the kind of the heteroatoms. Furthermore, the mass spectral differences between the oxygen and the sulfur derivatives and among the spiro derivatives bearing different number of ring members have also been studied.