Screening of the Pd-catalysed carboamination reaction conditions on hydrazine derivative 5a^a.

Entry	Pd cat	Lb	T (h)	Target spiro compounds		Isolated byproducts
				Yieldc (6a + 6a′%)	drd (6a : 6a′)	7 (%)	8 (%)	9 (%)
1	Pd(OAc)2	dpe-phos	12	0	—	32	53
2	Pd(OAc)2	TCP	12	45	1 : 2			49
3	Pd(OAc)2	TTP	3	87	1 : 1
4	Pd(OAc)2	TFP	3	87	1 : 1.5			13
5	PdCl2(MeCN)2	TFP	24	79	1 : 2			14
6	PdCl2(MeCN)2	BINAP	24	44	1 : 1	44		3
7	PdCl2(MeCN)2	PPh3	24	50	1 : 2			21
8	PdCl2(PPh3)2	—	24	25	1 : 1			29
9	Pd(PPh3)4	—	24	69	1 : 1.6	19
10	Pd2(dba)3	TTP	3	96	1.4 : 1			4
11	Pd2(dba)3	X-phos	3	98	1 : 1

^aReactions were carried out on a 0.25 mmol scale, with 1.0 equiv. of 5a, 1.3 equiv. of 4-bromo-1,1′-biphenyl, 1.3 equiv. of NaO^tBu, 4 mol% of Pd catalyst, 4 mol% of ligand, toluene (0.20 M).

^bDpe-phos = bis[(2-diphenylphosphino)phenyl]ether; BINAP= (±)-2,2′-bis(diphenylphosphino)-1,1′-binaphthalene; TFP = tris(2-furyl)phosphine; TCP = triscyclohexylphospine; TTP = tris(o-tolyl)phosphine; X-phos = 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl.

^cSum of the isolated yields for each diastereoisomer.

^dDetermined by ¹H NMR of the crude reaction product.