Table 2. TFP stability screening.

Entry	Conditions a	Stability (CDCl3)	Stability (MeOD)	Stability (CD3CN)
1	0.1 mL TFA	Stable	Stable	Stable
2	0.1 mL 12 M HCl	Stable	Stable	—
3	20 mg K2CO3	Stable	Unstable	Stable
4	20 mg tBuOK	Stable	Unstable	Unstable
5	20 mg NaH	Stable	—	Unstable
6	0.1 mL TEA b	Stable	Stable	Stable
7	0.1 mL DIPEA	Stable	Stable	Stable
8	0.1 mL SOCl2	Stable	Stable	Stable
9	20 mg NaBH4	Stable	Stable	Stable
10	20 mg I2	Stable	Stable	Stable
11	20 mg DCC	Stable	Stable	Stable
12	20 mg NaOH	—	Unstable	—

^aAll reactions were carried out in 0.7 mL of solvent with 10 mg of the tetrafluoropyridyl ether 2a.

^{b 1}H NMR resonances were seen to shift in the presence of TEA. Upon concentration under reduced pressure and resuspension in chloroform-d, the resonances were observed to shift back to their original positions.