The reaction of difluorocarbene with azirines affords a new type of azomethine ylides, viz.,
strained aziriniodifluoromethanides. 1,3Dipolar cycloadditions of ylides derived from
2unsubstituted 3arylazirines to dimethyl acetylenedicarboxylate and aldehydes give deriva
tives of 2,2difluoro1azabicyclo[3.1.0]hex3ene3,4dicarboxylic acids and 1,4oxazin
3(4H )ones, respectively. Ylides derived from 2mono and 2,2disubstituted azirines undergo
isomerization to 2aza1,3diene derivatives. 2,2Difluoro1azabicyclo[3.1.0]hex3enes are
transformed into 2fluoropyridine derivatives in high yields and react with amines to give
2,4diamino1azabicyclo[3.1.0]hex2ene derivatives.