Oxirination of the activated 3,4 -olefinic double bond of 8-(2-cyanoethyl) -8-azabicyclo[ 3.2.1] oct -3-en-2-one -6- carbonitrile (1) with basic hydrogen peroxide afforded 9-(2-cyanethyl)-1-oxa-9-azatricyclo 4.2.1.04,0 nonan-3-one-6-carbonitrile (2). Ring opening of the oxirane ring in (2) has been investigated, using 10% sodium hydroxide, acetic acid, and phenylhydrazine to give (4), (7) and (8) respectively. Structural and configurational assignments were deduced from IR, 'HNMR, UV and mass spectral evidence.