Download full text in PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... Efficient syntheses of the pyrrolizidine bases traechelanthamide ( ) and supinidine ( ) via an N-acyliminium ion rearrangement-cyclization are described. ... 2-azonia [3,3] sigmatropic rearrangements reported by Overman. For examples see: J. Am. Chem. Soc., 103 (1981), p. 5579 and ...