A general asymmetric route for the synthesis of the alexine and australine family of pyrrolizidine alkaloids. The first asymmetric synthesis of 1,2-diepi-alexine and 1,2,7-triepi-australine

The first asymmetric synthesis of 1,2-diepi-alexine and 1,2,7-triepi-australine (both are unknown at present) is described, which utilized the regioselective asymmetric aminohydroxylation (RAA) reaction of the achiral olefin VI, the cross metathesis (CM) reaction of the terminal olefin 8, and the formation and subsequent intramolecular double cyclization (DC) reactions of the epoxides 10 and 11. The C1 stereocenter was diastereoselectively introduced by the reaction of the aldehyde 7 with vinylmagnesium bromide.