Optimization of reaction parameters^a.

Entry	Variation from “standard conditions"	Yieldb,c (%)
1	None	(75)
2	Na2HPO4 instead of KOAc	86 (80)
3	NaOAc, LiOAc, K2CO3 or Cs2CO3 instead of KOAc	61–70
4	DMA, DMI or DMSO instead of p-xylene	0–28
5	0.25 M instead of 0.05 M	67
6d	O2 atmosphere instead of Ar atmosphere	4
7d	Degassed (bubbling with Ar)	92 (86)
8d	In the absence of KOAc	72

^aReactions were run on a 0.25 mmol scale.

^bYields were determined by ¹H NMR using an internal standard.

^cIsolated yields in parentheses.

^dNa₂HPO₄ was used instead of KOAc.