Table 1.

A General Synthesis of 2-Amido-Furans.

entry	ynamides	2-amido-furans	yield [%]:a	using Ab	Bc
1			18	82	44
2			19	65	48
3			20	77	48
4			25	50	24
5			26	47	29
6			27a	49	32
7			27b	58	35
8			27c	61	47
9			28	52	39
10			30a	45d	37e
11			30b	24d	22e

^aIsolated yields.

^bWhen using A, all reactions were run in toluene at 80 °C with 2 mol % Rh₂(OAc)₄, and ynamide concn = 0.15 M. Reagent A [3.0 equiv] was delivered over 1–2 h as a solution in toluene [concn = 0.30 M] via a syringe pump.

^cWhen using B, all reactions were run in CH₂Cl₂ at rt for 1.5 h with 5 mol % Rh₂(OAc)₄ and 4Å MS, and ynamide concn = 0.15 M. Reagent B [2.0 equiv] was delivered as solid in 0.5 equiv portions over 1 h.

^d4.0 equiv of A and 5 mol % Rh₂(OAc)₄ were used, and temp was 110 °C.

^eReactions were carried out in ClCH₂CH₂Cl [concn = 0.15 M] at 50 °C, and a total of 4.0 equiv of reagent B was used.