Catalytic, Enantioselective, Vinylogous Mannich Reactions

Asymmetric Synthesis of Rauhut–Currier type Products by a Regioselective Mukaiyama Reaction under Bifunctional Catalysis

“…Therefore, when the same reaction was catalyzed by triethylamine and the monofunctional squaramide 8 (Scheme ), a very low conversion (15%) and exclusively the 1,5-addition ( 9 ) were observed in the crude mixture. This is in agreement with all the previous catalytic reports described in the literature, − which are monofunctional systems and afford only 1,5-addition products. Therefore, our new approach allows a highly enantioselective and 1,3 regioselective functionalization of silyl dienolate derivatives, giving access to Rauhut–Currier products that previously were inaccessible through other methodologies …”

“…Different excellent and brilliant asymmetric metal catalyzed examples from Denmark’s, Katsuki’s, Campagne’s, Evans’s, and Carreira’s groups among others, as well as the organocatalytic examples from Schneider, Kalesse, List, and Deng, have shown that the most reactive position of the formal dienolate ( 1a ) is the remote C5-position (left, Scheme ). The orbital coefficients and electrophilic susceptibility are mainly responsible for this reactivity, provoking the observed 1,5 nucleophilic attack. It would be highly desirable if a catalyst could change to the 1,3-selectivity.…”

Development and Applications of Disulfonimides in Enantioselective Organocatalysis

“…δ-Amino-β-ketoesters are versatile building blocks, finding applications in the synthesis of numerous piperidine- and pyrrolidine-containing heterocyclic systems. Established methods allowing access to this class of compound are heavily reliant on enantioenriched compounds, such as those from the chiral pool or on employing chiral auxiliaries, whereas catalytic asymmetric methodologies are extremely rare. , Inspired by the findings outlined above, List and co-workers extended the scope of this type of transformation to allow enantioselective access to δ-amino-β-ketoester derivatives 56 utilizing the Mukaiyama–Mannich reaction manifold (Scheme ) …”

Relevant Developments in the Use of Three‐Component Reactions for the Total Synthesis of Natural Products. The last 15 Years

“…In 2012, the group of Schneider developed a threecomponent strategy toward the total synthesis of various substituted IBAs, which relied on a Brønsted acid catalyzed, highly enantioselective vinylogous Mukaiyama-Mannich reaction [24] between an acyclic silyl dienolate, a γ-oxoester, and para-anisidine to furnish γ-lactams as key intermediates. [25] This strategy, which resorted to the use of a few common versatile central building blocks that were made available on a multigram scale, enabled the enantioselective total synthesis of sixteen IBAs isolated from the skin of poisonous frogs, many of them for the first time (Scheme 3).…”