Table 2.

Preparation of 2,5-Disubstituted-1,3-oxazoles 3 via Displacement of the 2-Phenylsulfonyl Substituent

entry	lithium reagent	sulfone	oxazole producta,b	yieldc (%)
1		15	19	90
2		10	20	85
3		1	21	78
4		10	22	71
5		15	23	83
6		15	24	69
7		17	25	76
8		15	26	79
9		18d	27	81
10		15	28	82

^aReaction conditions: Lithium reagents (1.2 equiv or 2.2 equiv in entries 2 and 4) were added under N₂ to a THF solution of sulfones (0.053 mmol) at 0 °C. Reactions were generally complete within 5 minutes and warmed to 22 °C prior to addition of aq. NH₄Cl.

^bProducts were purified by flash silica gel chromatography.

^cAll yields are reported for isolated and purified products.

^dCompound 18 was prepared via the Stille cross-coupling reaction as described for 17.