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
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.
A silver(I) catalyzed regioselective trifluoromethylation of allenes using Langlois's salt (NaOSOCF3) is demonstrated. This transformation enables direct expedient access to α‐trifluoromethylated acroleins, which are valuable synthons for a number of pharmaceuticals and agrochemicals containing vinyl‐CF3 moieties. Versatility of this trifluoromethylation method has been established with good yield
Fluorinative Rearrangements of Substituted Phenylallenes Mediated by (Difluoroiodo)toluene: Synthesis of α-(Difluoromethyl)styrenes
作者:Zhensheng Zhao、Léanne Racicot、Graham K. Murphy
DOI:10.1002/anie.201706798
日期:2017.9.11
(difluoroiodo)toluene in the presence of 20 mol % BF3⋅OEt2 to yield α‐difluoromethyl styrenes. This unprecedented reaction was entirely chemoselective for the internal allene π bond, and showed remarkable regioselectivity during the fluorination event. Substituted phenylallenes, phenylallenes possessing both phenyl‐ and α‐allenyl substituents, and diphenylallenes were investigated, and good functional‐group