Helferich method explained

The Helferich method may refer to:

• Glycosylation of an alcohol using a glycosyl acetate as glycosyl donor and a Lewis acid (e.g. a metal halide) as promoter^[1]
• Glycosylation of an alcohol using a glycosyl halide as a glycosyl donor and a mercury salt as promoter (cf the Koenigs-Knorr reaction, which uses silver salts as promoters)^[2]

Notes and References

1. B. Helferich, E. Schmitz-Hillebrecht, Ber. 66, 378 (1933)
2. B. Helferich, J. Zirner, Chem. Ber. 95, 2604 (1962)