Table 3. Scope of propargyl ether ^a .

Propargyl ether	Product	Yield b /%
		91%
		86%
		81% c
	4d consumed; no rxn of indole	0%
		90%

^aReaction conditions: 1 equiv. of 4a–e, 1 equiv. of 5a, and 5 mol% of catalyst (0.2 M) for 10 h in air.

^bIsolated yield.

^c1.5 equiv. of 5a.

^d2.0 equiv. of 4e.