1,3-bisindolyl compounds

Bandini and Umani-Ronchi et al. again used InBr3 in the syntheses of 1,3-bisindolyl compounds after confirming its superiority over AICI3 and InCl3. In addition, they found that the addition of TMSCl increased yield and halved the reaction time [55] (Figure 8.29). 

Fig. 8.29 Syntheses of 1,3-bisindolyl compounds through a Michael addition strategy.

Of special importance to the synthesis was the choice of condensing agents and cbnditions. HATU-HOAF was of particular value in these final stages. Condensation of the threonine carboxyl of 24 (from Scheme 5) with the pyrrolidine N s of the bisindolyl compound 15 (from Scheme 3) afforded 25. Removal... 

The possibility of replacing all three phenyl rings in the triarylmethane lactone structure by heterocycles has also been exploited. The first compound to be described83 was the 3,3-bisindolyl-7-azaphthalide (18). This... 

---