Table 1.

Optimization results for the XtalFluor-E^® mediated N,O-acetal formation of enamide

Entry	Solvent	Time (h)	Conversion (yield)a
1b	MeOH	36	99% (>98%)
2	MeOH	48	88% (57%)
3	Toluene	22	74% (66%)
4	CH2Cl2	10	95% (89%)
5	CHCl3	10	93% (83%)
6	Nitromethane	10	95% (85%)
7	ClCH2CH2Cl	10	95% (85%)
8	Acetonitrile	22	85% (68%)
9c	CH2Cl2	36	97% (86%)
10d	CH2Cl2	8	100% (>98%)

^aYields were estimated by ¹H NMR analysis of the crude reaction mixture.

^bOne equivalent of XtalFluor-E^® was used

^cXtalFluor-M^® (10 mol%) was used instead of XtalFluor-E^®.

^dMeOH:DCM (1:1 v:v, 0.1 M) was used.