The synthesis of anatoxin-a (1) was completed by using the cycloaddition of 1-pyrroline 1- oxide (2) onto dienol (6), a reaction which proceeded with high stereoselectivity, regioselectivity, and site selectivity. The resultant adduct (ie 7) was oxidized to a second nitrone (ie 8) which undergoes a second closure to afford cycloadduct 9a with regiospecificity. The conversion of 9a into anatoxin-a hydrochloride (1· HC1) was both ...
