Synthesis of Aristotelia-Type Alkaloids

Article abstract of DOI:10.1002/hlca.19900730209

Biomimetic syntheses of racemic aristomakinine ((+/-)-3) and aristomakine ((+/-)-4), an unusual indole alkaloid bearing an N-isopropyl group, are described.The key step is a Grob-type fragmentation of anti-15-aristotelinyl methanesulfonate ((+/-)-2) to the intermediate iminium ion I which, upon subsequent hydrolysis, furnished aristomakinine ((+/-)-3).On the other hand, the same intermediate could be reduced in situ to aristomakine ((+/-)-4).The controversial relative configurations of the two alkaloids have been firmly established by means of NOE difference experiments.