Efficient Synthesis ofN-Prenylpyrroloindoline andN-Prenylindole Alkaloids Based on a New Four-Reaction Anionic Domino Process

Treatment of 2,5-diketopiperazines or carbamates derived from tryptophan or tryptamine with iodomethyltrimethylsilane followed by lithium hexamethyldisilazane and a prenyl halide produced stereoselectively derivatives of the hexahydropyrrolo[2,3-b]indole system bearing prenyl substituents both at C-3a and at the indoline nitrogen in a one-pot procedure involving a novel four-reaction anionic domino process. The reaction was applied to the preparation of N-prenyltryprostatin B and to achieving a very efficient formal total synthesis of the biologically active marine natural product (+/-)-debromoflustramine B.