Synthetic and Structural Studies of the Lolium Alkaloids

Article abstract of DOI:10.1021/jo00332a025

Application of transannular cyclizations to the synthesis of bridged pyrrolizidine alkaloids such as loline (1) is described.The general method involves bromination of 3-aza-9-oxabicyclo<4.2.1>non-7-ene (5), leading directly to the skeleton (12a) of the lolium alkaloids.Unsuccessful attempts to replace the bromine are described.The X-ray structure of the synthetic compound 12a as well as loline itself (1) and the biogenesis of lolium alkaloids are also discussed.