Table 1. Optimization of catalytic α-alkynylation of 1-(2-alkynyl) cyclic amine 1a with 2a ^a .

Entry	Catalyst	Time (h)	Yield of 3aa b (%)	Recovery of 1a b (%)
1	CuBr	12	13	64
2	CuBr2	10	13	—
3	ZnCl2	10	24	—
4	ZnBr2	10	39	—
5	AgOTf	12	5	95
6	CdI2	10	40	—
7	CdBr2	24	42	53
8 c	CdBr2	36	56	20
9 d	CdBr2	12	47	26

^aThe reaction was conducted using 1a (1.0 mmol) and alkyne 2a (2.0 mmol) in 6 mL of dioxane at 110 °C.

^bDetermined by ¹H NMR analysis with CH₂Br₂ as the internal standard.

^cThe reaction was conducted at 120 °C.

^dThe reaction was conducted at 130 °C.