Table 2. Optimization of reaction conditions for catalytic α-alkynylation of N-internal 2-alkynylic cyclic amine 1a with 2a ^a .

Entry	X	Solvent	t (h)	Yield of 3aa b (%)	Recovery of 1b b (%)
1	20	DMF	23	43	25
2	20	DMSO	23	20	35
3	20	Toluene	23	40	—
4	20	THF	23	48	—
5	20	DCE	23	3	—
6	20	CH3CN	23	39	—
7	20	t BuOMe	36	63	—
8	15	t BuOMe	36	64	—
9 c	10	t BuOMe	36	66	—
10	5	t BuOMe	36	69	10

^aThe reaction was conducted using 1a (0.5 mmol) and alkyne 2a (1.0 mmol) in 3 mL of solvent.

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

^cThe reaction was conducted using 1a (1.0 mmol) and alkyne 2a (2.0 mmol) in 6 mL of ^tBuOMe at 120 °C.