2007
9. An Efficient Metal-Catalyzed Hydroalkylation
Magnus Rueping, Boris J. Nachtsheim, Alexander Kuenkel
Synlett 2007, 1391-1395
ABSTRACT:
An efficient metal-catalyzed hydroalkylation of various styrenes, norbornene, and cyclohexadiene with 1,3-dicarbonyl compounds has been developed. This new bismuth-catalyzed C-H functionalization provides the corresponding alkylated pentanediones in good to excellent isolated yields after short reaction times.
Magnus Rueping, Erli Sugiono, Fenja R. Schoepke
Synlett 2007, 1441-1446
7. An Enantioselective Chiral Brønsted Acid Catalyzed Imino−Azaenamine Reaction
Magnus Rueping, Erli Sugiono, Thomas Theissmann, Alexander Kuenkel, Angela Köckritz, Anahit Pews-Davtyan, Navid Nemati, Matthias Beller
Org. Lett. 2007, 9, 1065-1068
ABSTRACT:
The enantioselective Brønsted acid catalyzed addition of methyleneaminopyrrolidine to N-Boc imines has been achieved in the presence of chiral phosphoric acids derived from 3,3‘-di(phenanthryl)-H8-BINOL. The corresponding aminohydrazones have been isolated in good yields with enantiomeric excesses up to 90%.
6. Metal‐Free, Enantioselective Strecker Reactions Catalyzed by Chiral BINOL and TADDOL Catalysts
Magnus Rueping, Erli Sugiono, Stefan A. Moreth
Adv. Synth. Catal. 2007, 349, 759-764
ABSTRACT:
An efficient, metal-free Brønsted acid-catalyzed, enantioselective hydrocyanation of ketoimines has been developed. This BINOL phosphate-catalyzed Strecker reaction provides the corresponding amino nitriles, precursors of quaternary amino acids, in good isolated yields and enantioselectivities. Additionally, we demonstrate that chiral diols, such as TADDOL, are effective enantioselective catalysts for the hydrogen-bond activation of aldimines.
5. Efficient Metal-Catalyzed Direct Benzylation and Allylic Alkylation of 2,4-Pentanediones
Magnus Rueping, Boris J. Nachtsheim, Alexander Kuenkel
Org. Lett. 2007, 9, 825-828
ABSTRACT:
A highly effective metal-catalyzed benzylation and allylic alkylation of 2,4-pentanediones has been developed. This new bismuth-catalyzed direct carbon−carbon bond forming reaction provides the corresponding monoalkylated dicarbonyl compounds in high yields after short reaction times using the lowest amounts of catalyst (1 mol %) and the free alcohol. In addition, a new route to substituted indenes is presented.
4. A Manganese-Catalyzed Cross-Coupling Reaction
Magnus Rueping, Winai Ieawsuwan
Synlett 2007, 247-250
ABSTRACT:
A manganese-catalyzed cross-coupling reaction of heterocyclic chlorides with aryl- as well as alkylmagnesium halides has been developed. The reaction provides a variety of heterocyclic compounds under mild and practical reaction conditions using low amounts of manganese chloride as catalyst.
Magnus Rueping, Winai Ieawsuwan, Andrey P. Antonchick, Boris J. Nachtsheim
Angew. Chem. Int. Ed. 2007, 46, 2097-2100
ABSTRACT:
Low catalyst loadings, high enantioselectivities, mild conditions, and fast reaction times are the important features of the first enantioselective organocatalytic electrocyclic reaction: a Nazarov cyclization leading to the synthesis of substituted five-membered rings with a chiral Brønsted acid as a catalyst (see scheme). A further advantage of this method is the possible entry to all four diastereomers of the product.
2. Organocatalytic Enantioselective Reduction of Pyridines
Magnus Rueping, Andrey P. Antonchick
Angew. Chem. Int. Ed. 2007, 46, 4562-4565
ABSTRACT:
The first enantioselective organocatalytic reduction of pyridine derivatives leads to hexahydrochinolinones and tetrahydropyridines in good yields and with excellent enantioselctivities (up to 92 % ee; see scheme). These compounds are starting materials for the synthesis of various natural products.
Magnus Rueping, Andrey P. Antonchick, Claus Brinkmann
Angew. Chem. Int. Ed. 2007, 46, 6903-6906
ABSTRACT:
The combination of enantioselective Brønsted acid catalyzed activation and metal-catalyzed alkynylation of α-imino esters under mild reaction conditions leads to amino acids in high yields and with excellent e.r. values (see scheme; PG=protecting group).