Diastereoselective Spirocyclization of Imines of 2-Substituted 1H-Indole-3-ethylamines ( = Trypatamines): Variation of the electrophile and the substituent at C(2) and its influence on the steric outcome. 6th Communication on indoles, indolenines, and indolines

Tryptimines of type 7 form with various acyl halogenides EX preferentially tricycles of type 8 (cf: Scheme 2). The homochiral imines 9 and 17 are transformed into (2′R,3S)-configurated products. The synthetic and mechanistic importance of these results is discussed.