Ap. Molchanov et al., Reactions of substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acid esters with halogens, RUSS J ORG, 37(1), 2001, pp. 128-135
Substituted 2,3,7-triazabicyclo[3.3.0]oct-3-ene-4-carboxylic acid esters re
act with chlorine and bromine to give the corresponding 4-halo-2,3,7-triaza
bicyclo[3.3.0]oct-2-ene-4-carboxylates. Heating of the latter to 120 degree
sC under reduced pressure leads to elimination of nitrogen molecule and for
mation of 6-halo-3-azabicyclo[3.1.0]hexane-5-carboxylates.