Yg. Gololobov et al., Intramolecular electrophilic rearrangements in saturated acyclic systems. Reactions of bis-carbanions with isocyanates, RUSS CHEM B, 50(5), 2001, pp. 838-842
The reactions of mono- and bis-isocyanates with bis-carbanions whose COOAlk
groups at the anionic centers do not contain acidic hydrogen atoms proceed
unusually to form bis-carbamates (including oligomeric carbamates) due to
migration of the alkoxycarbonyl groups from the carbon to the nitrogen atom
.