An enantioselective alkoxycarbonylation-amination cascade process of terminalallenes with CO, methanol, and arylamines has been developed. It proceeds under mild conditions (room temperature, ambient pressure CO) via oxidative Pd(II) catalysis using an aromatic spiroketal-based diphosphine (SKP) as a chiral ligand and a Cu(II) salt as an oxidant and affords a wide range of α-methylene-β-arylamino
Palladium-Catalyzed Oxidative Carbonylative Coupling of Arylallenes, Arylboronic Acids, and Nitroarenes
作者:Hui-Qing Geng、Jin-Bao Peng、Xiao-Feng Wu
DOI:10.1021/acs.orglett.9b02925
日期:2019.10.18
In this Letter, a palladium-catalyzed multicomponent procedure for the selective synthesis of α-substituted α,β-unsaturated ketones has been developed. With readily available allenes, arylboronicacids, and nitroarenes as the substrates, the reaction proceeds selectively to the desired α-substituted enones. Notably, no manipulation of carbon monoxide gas is needed here, and Mo(CO)6 has been applied
Intermolecular Allene Functionalization by Silver-Nitrene Catalysis
作者:Manuel R. Rodríguez、María Besora、Francisco Molina、Feliu Maseras、M. Mar Díaz-Requejo、Pedro J. Pérez
DOI:10.1021/jacs.0c04395
日期:2020.7.29
Under silver catalysis conditions, using [Tp*,BrAg]2 as the catalyst precursor, allenes react with PhI=NTs in the first example of efficient metal-mediated intermolecular nitrenetransfer to such substrates. The nature of the substituent at the allene seems crucial for the reaction outcome since arylallenes are converted into azetidine derivatives whereas methylene aziridines are the products resulting
(B2(Pin)2) to approach functionalized dibenzo[b,f][1,4]oxazepine derivatives is developed. The chiral products are obtained in up to 81% yield, >20:1 dr, and 98% ee when either a chiral diphosphine ligand or a chiral ferrocenyl‐based P,N‐ligand is used. Furthermore, the reaction exhibits reversed diastereoselectivities when the chiral diphosphine ligand and the chiral P,N‐ligand are used respectively.
Highly Selective Cobalt-Mediated [6 + 2] Cycloaddition of Cycloheptatriene and Allenes
作者:Hervé Clavier、Karel Le Jeune、Innocenzo de Riggi、Alphonse Tenaglia、Gérard Buono
DOI:10.1021/ol102783x
日期:2011.1.21
[6 + 2] Cycloadditions between cycloheptatrienes with allenes have been investigated. Cobalt salts were found to promote this transformation efficiently. Moreover, this reaction was found to be highlyselective since only one regioisomer was obtained with an excellent E/Z-selectivity.