Table 1.

Amide and Weinreb amide synthesis using PPh₃/I₂.^[a]

Entry	Acid	Amine	Time	Yield
1			4 h	77%[2g]
2			1.5 h	77%[19]
3			12 h	60%[20]
4			1 h	74%[21]
5			2 h	85%[22]
6			2 h	77%[23]
7			2 h	83%[24]
8			1.5 h	83%
9			0.5 h	78%[25]
10			3 h 3 h	52%[24] 72%[b]
11			0.5 h	83%[26]
12			1 h 1 h	63%[27] 72%[c]
13			12 h	80%[28]
14			1 h 1 h	56%[29] 73%[c]
15			2 h 2 h	45%[29] 67%[c]
16			13 h 13 h	44%[30] 53%[c]
17			3 h 1 h	48%[31] 65%[c]
18			1 h	70%[32,d]
19			1 h	65%[33,d]

^[a]Reactions were conducted using 1 mmol each of PPh₃, I₂ carboxylic acid, amine, and 1.5 mmol of iPr₂NEt in 4 mL of CH₂Cl₂, unless noted otherwise.

^[b]Yield obtained by using 2 molar equiv each of PPh₃ and I₂, and 1.5 molar equiv of o-toluidine.

^[c]Yield obtained by using 2 molar equiv each of PPh₃ and I₂.

^[d]2.5 Molar equiv of iPr₂NEt was used.