Does the Dieckmann Condensation Occur in the Gas Phase ?

Article abstract of DOI:10.1002/oms.1210231008

Burinsky and Cooks have reported that deprotonated dimethyl adipate eliminates methanol via a gas-phase Dieckmann condensation.This is in contrast to the behaviour of simple methyl ester enolates which lose MeOH by a different mechanism, e.g.MeOCOCHCH2R -> -> O=C=CHCHR + MeOH.Evidence is presented which supports the Dieckmann mechanism for adipates.For example, MeOCOC(Me)CH2CH2CD(Me)CO2Me should eliminate MeOD in a Dieckmann condensation, but MeOH by the alternative mechanism outlined above.Experimentally , MeOD is lost exclusively.Similarly, MeOCOCDCH2CH2C(Me)2CO2Me also loses MeOD, consistent with a Dieckmann process