240
M. Rueping, E. Sugiono
Table 10 Scope of the double Brønsted acid catalyzed Mannich–Michael reaction
of the second achiral Bronsted acid BH, the acetic acid, via an accelerated adjustment of the keto-enol-equilibrium. (The rate-determining
step of the reaction is presumably the dienol formation, as no considerable conversion was observed without the addition of achiral Brønsted
acid.) The subsequent Mannich reaction provides the adduct B, an exceptionally reactive Michael acceptor, which leads directly to the corresponding isoquinuclidine 28 as well as the regenerated chiral BINOLphosphate 5.
The development of this so far unprecedented, double Brønsted acid
catalyzed enantioselective synthesis of various aromatic and heteroaro-
M. Rueping, E. Sugiono
Table 10 Scope of the double Brønsted acid catalyzed Mannich–Michael reaction
of the second achiral Bronsted acid BH, the acetic acid, via an accelerated adjustment of the keto-enol-equilibrium. (The rate-determining
step of the reaction is presumably the dienol formation, as no considerable conversion was observed without the addition of achiral Brønsted
acid.) The subsequent Mannich reaction provides the adduct B, an exceptionally reactive Michael acceptor, which leads directly to the corresponding isoquinuclidine 28 as well as the regenerated chiral BINOLphosphate 5.
The development of this so far unprecedented, double Brønsted acid
catalyzed enantioselective synthesis of various aromatic and heteroaro-