SINGLET AND TRIPLET NITRENES .3. ADDITION OF CARBETHOXYNITRENE TO 1,3-DIENES

Carbethoxynitrene adds to the double bonds of isoprene to give two isomeric aziridines. At high isoprene concentrations, where the singlet nitrene predominates, theadducts are formed in approximately equalamounts. At low isoprene concentrations, where much of the nitrene has time to go to the triplet state, the methyl-substituted double bond is preferred. No 1,4-addition product could be detected. The addition of the nitrene to cyclopentadiene and1,3-cyclohexadiene also did not give 1,4-addition products, but only aziridines and substances derived from them, such as oxazolines. The N-carbethoxy-2-methyl-2-vinylaziridine underwent a new thermal rearrangement to give N-carbetho y-3-methyl-3-pyrroline. © 1968, American Chemical Society. All rights reserved.