Table 1. Identification of Reaction Conditions for the Formation of Diindolylamines using Buchwald–Hartwig Amination.

	reaction conditions
	indole		catalyst
entry	NH2	Br	precatalyst	ligand	base	solvent	productsa
1	7	5a	Pd(dppf)Cl2	dppf	NaOtBu	1,4-dioxane	N.R.
2	7	5a	Pd(OAc)2	XPhos	Cs2CO3	t-BuOH	N.R.
3	7	5a	Pd2(dba)2	XPhos	NaOtBu	t-BuOH	N.R.
4	7	5a	Pd(OAc)2	XPhos	K2CO3	t-BuOH	9a (incomplete conversion)
5	6	4b	Pd(OAc)2	XPhos	K2CO3	t-BuOH	8b
							4a
6	6	4b	Pd(OAc)2	XPhos	KOtBu	t-BuOH	4a major
							8b trace
7	6	4b	Pd(OAc)2	XPhos	K2CO3/Et3N	t-BuOH	8a trace and unknown
8	6	4b	Pd(OAc)2	BrettPhos	K2CO3	t-BuOH	8a
							4a
9	7	5a	Pd(OAc)2	BrettPhos	K2CO3	t-BuOH	9a major

^aN.R., no reaction.