TRANS-ANNULAR CYCLIZATIONS OF 1-AZA-4-CYCLOOCTENE

The stereospecific, transannular cyclizations of l-aza-4-cyclooctene (1) are described. Compound 1 reacts with electrophiles (Br2 I2, HgCl2 PhSBr, PhSeBr) to produce 1-substituted pyrrolizidines 6. The stereochemistry of the bromine-induced cyclization was determined by X-ray crystallography. The reaction proceeds via transannular reaction of the nitrogen with the corresponding “onium” ion. There is no evidence of through-space (transannular) interaction of the amine and the double bond by PES. © 1979, American Chemical Society. All rights reserved.