A simple and efficient palladium-catalyzed intramolecular carbonylativesynthesis of isocoumarins and phthalides from the easily available starting materials by employing phenylformate as a CO surrogate has been achieved. The approach affords target compounds in good to excellent yields with the advantages of lower toxicity, milder conditions, easy operation and wide functional group tolerance.
Synthesis of Benzo[b]furans by Palladium-NHC Catalyzed Ring Closure of o-Bromobenzyl Ketones
作者:András Kotschy、János Faragó
DOI:10.1055/s-0028-1083261
日期:2009.1
The palladium-catalyzed ringclosure of aryl o-bromobenzyl ketones, easily accessible from aromatic aldehydes and 2-bromobenzyl bromide, provides a straightforward route to 2-arylbenzofurans. A study of the ringclosure revealed that a heterocyclic carbene based catalyst provides the best results. ringclosure - palladium - catalysis - benzofurans
New Preparation of Benzylic Aluminum and Zinc Organometallics by Direct Insertion of Aluminum Powder
作者:Tobias D. Blümke、Klaus Groll、Konstantin Karaghiosoff、Paul Knochel
DOI:10.1021/ol202733v
日期:2011.12.16
benzylic aluminum sesquichlorides under mild conditions (THF, 20 °C, 3–24 h) without homocoupling (<5%). These new benzylic organometallics reacted smoothly with various electrophiles (Pd-catalyzed cross-couplings, or Cu-mediated acylations, allylations, or 1,4-addition reactions). Electron-poor benzylic chlorides or substrates prone to Wurtz coupling can be converted to benzylic zinccompounds by the
Preparation of Functionalized Organomanganese(II) Reagents by Direct Insertion of Manganese to Aromatic and Benzylic Halides
作者:Zhihua Peng、Paul Knochel
DOI:10.1021/ol201109g
日期:2011.6.17
arylmanganese compounds were prepared using commercial manganese powder in the presence of LiCl and catalyticamounts of both 2.5% InCl3 and 2.5% PbCl2 (THF, 0–50 °C). In addition, benzylic manganese reagents are obtained at 25 °C in ca. 70–80% yield (in the absence of LiCl) using commercial manganese powder and catalyticamounts of 2.5% InCl3 and 2.5% PbCl2. The resulting organomanganese reagents undergo
novel nickel catalyst for the reaction of tert-butyl isocyanide insertion was discovered. In this approach, 1,2-bis(diphenylphosphino)ethane (L3) serves as an efficient ligand, thereby allowing the preparation of lactones from (o-bromophenyl)phenylethanone derivatives. It is noteworthy that this is the first example of nickel acting as a metal catalyst in the reactions of tert-butyl isocyanide insertion