A convenient method for the synthesis and resolution of Tröger base

Racemic Tröger base 1 can be readily obtained by the condensation of 4-toluidine and paraformaldehyde in the presence of Lewis acids and easily resolved via the preparation of diastereomeric aggregates using chiral dibenzoyl-l-tartaric acid 2.

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Tröger’s baseC17H18N2Ee ⩾98%[α]D25=-301 (c 0.22, hexane)Source of chirality: resolutionAbsolute configuration: (5R,11R)