Enantiodivergent Synthesis of (+)- and (-)-Anatoxin from L-Glutamic acid

Article abstract of DOI:10.1021/jo00304a012

The optically pure 2,5-difunctionalized homotropane 11, prepared from L-glutamic acid, serves as the common, advanced intermediate for the synthesis of either natural (+)-anatoxin (30, 18percent overall yield) or unnatural (-)-anatoxin (33, 30percent overall yield) by selective manipulation of either the C-2 ester or C-5 acetyl functionalities.Side-chain substitution in the decarbonylative iminium ion cyclization of a substituted proline enhanced the yield by 25percent as compared to the unsubstituted parent system.The additional substitution at C-5 of the 9-azabicyclo<4.2.1>nonane ring system allows access to analogues of anatoxin not availalble through other syntheses.