Total Syntheses of (-)-7-epi-Alexine and (+)-Alexine Using Stereoselective Allylation

Total syntheses of (-)-7-epi-alexine and (+)-alexine were achieved by using stereoselective allylation via a functionalized pyrrolidine obtained from an extended chiral 1,3-oxazine. The synthetic strategies include pyrrolidine formation via oxazine cleavage and diastereoselective allylations of a pyrrolidine aldehyde. (-)-7-epi-Alexine and (+)-alexine were synthesized from anti syn anti-oxazine in 12 steps.