An ab initio study of the rearrangement of carbonyl compounds to oxacarbenes

As the first part of a systematic theoretical study of oxacarbene rearrangement, ab initio SCF MO calculations employing a split valence shell basis set have been carried out for the model conversion of formaldehyde to the corresponding oxacarbene. The various cross‐sections of the reaction hypersurface were obtained by complete geometry optimization. The results suggest that, at least for the present model system, the reaction takes place preferentially in the first triplet (T1) state via a concerted pathway.