Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

• Maroš Bella,
• Bohumil Steiner,
• Vratislav Langer and
• Miroslav Koóš

Beilstein J. Org. Chem. 2014, 10, 1942–1950, doi:10.3762/bjoc.10.202

• resulted from an unexpected benzyl to o-tolyl rearrangement. The proportion of benzyl versus o-tolyl derivatives depended on the reaction conditions. Benzylmagnesium chloride afforded predominantly o-tolyl carbinols while the application of benzylmagnesium bromide led preferably to the o-tolyl carbinols

• possible mechanism for the Grignard reaction leading to the benzyl→o-tolyl rearrangement is also proposed. Keywords: aldehyde; benzyl versus o-tolyl; carbohydrate; Grignard reaction; rearrangement; X-ray crystallography; Introduction One of the most popular synthetic routes leading to the formation of