Table 2.

O-Glycosylations of cis-3,5-dibenzyoxy oxepane thioacetal

			trans-13 : cis-13b
Entry	Nucleophile	Fa	Without TfOc (A)	With TfOd (B)
1	18	> 0.38	84 : 16	82 : 18
2	19	0.38	52 : 48	16 : 84
3	20	0.29	47 : 53	8 : 92
4	21	0.15	52 : 48	52 : 48
5	22	0.13	47 : 53	68 : 32
6	23	0	41 : 59	66 : 34

^aField inductive effect parameter of R²; lower F value indicates higher nucleophilicity.¹⁶

^bDiastereomeric ratios were determined from ¹³C and ¹H NMR spectroscopic analysis of the crude product mixture.¹⁴ Relative stereochemistry was determined by J coupling constants and NOE experiments.¹⁵

^cNIS, CH₂Cl₂, −78 °C.

^dNIS, AgOTf, CH₂Cl₂, −40 °C.