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
In this communication, a highly selective palladium-catalyzed carbonylative four components procedure for the transformation of allenes, alcohols and nitroarenes has been developed. The desired 2-aminomethyl substituted 3-arylacrylates were produced in good yields with Mo(CO)6 as the solid CO source. Furthermore, nitroarenes have been used as reaction partners and oxidant in this catalytic system.
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
A distinct copper-catalyzed boroacylation of allenes with acylchlorides and bis(pinacolato)diboron is developed. For aromatic acylchlorides, 1,2-boroacylation of allenes readily takes place, leading to the formation of tetrasubstituted vinylboronates with exclusive (E)-stereoselectivity. In comparison, the employment of alkyl acylchlorides as electrophiles alters the selectivity to 2,3-boroacylated
开发了一种独特的铜催化丙二烯与酰氯和双(频哪醇)二硼的硼酰化反应。对于芳族酰氯,丙二烯很容易发生 1,2-硼酰化,导致形成具有排他性 ( E )-立体选择性的四取代乙烯基硼酸酯。相比之下,使用烷基酰氯作为亲电试剂会改变对 2,3-硼酰化产物的选择性。此外,该产品可以很容易地进行 Suzuki-Miyaura 交叉偶联,得到完全保留构型的四取代烯烃。
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