effective asymmetriccatalysts (0.5–5.0 mol % catalyst loading) for a variety of reactions with α,β‐unsaturated carbonyl compounds, namely Friedel–Crafts alkylations (94–99 % ee), Michael additions with CH‐acidic compounds (81–97 % ee), and a variety of cycloadditions (92–99 % ee with high d.r.). Mechanistic investigations and crystal structures of an iridium‐coordinated substrates and iridium‐coordinated
A highly stereoselective vinylogousMukaiyamaMichael reaction (VMMR) leading to α‐keto phosphonate‐containing γ‐butenolides with two stereogenic centers is described. The presented transformation is catalyzed by a combination of a commercially available C2‐symmetric bisoxazoline (BOX) ligand and a copper salt and tolerates a variety of nucleophiles and electrophiles. The stereoselectivities of the
rocks! Proline and (2S,3aS,7aS)‐octahydro‐1H‐indole‐2‐carboxylic acid are both poor catalysts for the inverse‐electron‐demand hetero‐Diels–Alder reactions between aldehydes and electron‐deficient enones. However, forming modularly designed organocatalysts (MDOs) through their self‐assembly with cinchona alkaloid‐derived thioureas can dramatically improve the efficiency of these catalysts (see scheme;
Organocatalytic Asymmetric Michael/Cyclization Cascade Reactions of 3-Hydroxyoxindoles/3-Aminooxindoles with α,β-Unsaturated Acyl Phosphonates for the Construction of Spirocyclic Oxindole-γ-lactones/lactams
Enantioselective Michael/cyclization cascade reactions of 3-hydroxyoxindoles/3-aminooxindoles with α,β-unsaturatedacyl phosphonates by using a cinchonine derived squaramide as the catalyst were developed. A broad range of spirocyclic oxindole-γ-lactones/lactams could be obtained in moderate to excellent yields (up to 98%) with good to excellent diastereo- and enantioselectivities (up to >99:1 dr and
Catalytic Enantioselective Friedel-Crafts Alkylation of Indoles with β,γ-Unsaturated α-Keto Phosphonates in the Presence of Chiral Palladium Complexes
作者:Dae Kim、Young Kang、Ki Suh
DOI:10.1055/s-0030-1259932
日期:2011.5
The catalytic enantioselective Friedel―Crafts alkylation reaction promoted by chiralpalladium complexes is described. The treatment of indoles with β,γ-unsaturated α-ketophosphonates under the mild reaction conditions afforded the corresponding Friedel―Crafts alkylation adducts with excellent enantioselectivities (up to 99% ee).