Biomimetic Organocatalytic C–C-Bond Formations
85
Scheme 19. Catalytic cycle of the benzoin condensation as proposed by Breslow
scale. They could utilize this synthetic concept for the preparation of
numerous α-hydroxy ketones. Aliphatic aldehydes showed the best results with catalyst 86a, whereas, for aromatic substrates the thiazolium
salts 86b or 86c were better catalysts (Fig. 11) (Stetter et al. 1976; Stetter and Kuhlmann 1991).
Fig. 11. Thiazolium salts utilized by Stetter et al.
85
Scheme 19. Catalytic cycle of the benzoin condensation as proposed by Breslow
scale. They could utilize this synthetic concept for the preparation of
numerous α-hydroxy ketones. Aliphatic aldehydes showed the best results with catalyst 86a, whereas, for aromatic substrates the thiazolium
salts 86b or 86c were better catalysts (Fig. 11) (Stetter et al. 1976; Stetter and Kuhlmann 1991).
Fig. 11. Thiazolium salts utilized by Stetter et al.