Experimental and theoretical mechanistic studies on the Cu(OTf)2-catalyzed hydroamination reaction of terminal allenes with secondary amines reveal that in situ generated cationic Cu(I) is the catalytically active species and explain the observed regio- and stereoselectivity for the unbranched E product. Insight into the structure of the relevant transition states allowed the generalization of this
designed synthetic approach also lies in the use of N-allenamides as substrates, which, after the addition of the first electrophilic radical, preserve a further reactive π-system, making possible the addition of a second α-keto radical and enabling the installation of a keto functionality at a remote position. The good yields, the broad scope, and the possibility to further synthetically elaborate
Gold(I)‐Catalyzed [8+2]‐Cycloaddition of 8‐Aryl‐8‐azaheptafulvenes with Allenamides and Ynamides: Regioselective Synthesis of Dihydrocycloheptapyrrole Derivatives
作者:Tatiana Suárez‐Rodríguez、Ángel L. Suárez‐Sobrino、Alfredo Ballesteros
DOI:10.1002/chem.202005348
日期:2021.4.26
higher‐order [8+2] cycloadditions of 8‐aryl‐8‐azaheptafulvenes 1 with allenamides 2 and ynamides 3 were studied. 1,8‐Dihydrocycloheptapyrroles 4 were achieved by a regioselective [8+2] cycloaddition of azaheptafulvenes 1 and allenamides 2 in the presence of (2,4‐ditBuC6H3O)3PAuNTf2 as catalyst. Besides, ynamides 3 and 8‐aryl‐8‐azaheptafulvenes 1, undergo a regioselective [8+2] cycloaddition, to give 2‐amido‐1
Hydroarylation of
<i>N</i>
‐Allenyl Derivatives Catalyzed by Copper**
作者:Racha Abed Ali Abdine、Lucas Pagès、Marc Taillefer、Florian Monnier
DOI:10.1002/ejoc.202001333
日期:2020.12.31
The regio‐ and stereoselective addition of (hetero)aryl nucleophiles to N‐allenyl derivatives is described under copper catalysis. represents the first example of hydroarylation of allenes catalyzed by copper.
Regioselective Alkylative Carboxylation of Allenamides with Carbon Dioxide and Dialkylzinc Reagents Catalyzed by an N-Heterocyclic Carbene-Copper Complex
reaction was alkylative zincation of the allenamides to give an alkenylzinc intermediate followed by nucleophilic addition to CO2. A variety of cyclic and acyclic allenamides were found to be applicable to this transformation. Dialkylzinc reagents bearing β‐hydrogen atoms, such as Et2Zn or Bu2Zn, also gave the corresponding alkylative carboxylation products without β‐hydride elimination. The present