Rhodium(III)‐Catalyzed Synthesis of Skipped Enynes via C(sp
<sup>3</sup>
)–H Alkynylation of Terminal Alkenes
作者:Franco Della‐Felice、Margherita Zanini、Xiaoming Jie、Eric Tan、Antonio M. Echavarren
DOI:10.1002/anie.202014877
日期:2021.3.8
The RhIII‐catalyzedallylicC−H alkynylation of non‐activated terminalalkenes leads selectively to linear 1,4‐enynes at room‐temperature. The catalytic system tolerates a wide range of functional groups without competing functionalization at other positions. Similarly, the vinylic C−H alkynylation of α,β‐ and β,γ‐ unsaturated amides gives conjugated Z‐1,3‐enynes and E‐enediynes.
A general and efficient intramolecular halo-amination of unactivatedalkenes for the synthesis of various halogenated N-heterocycles was developed via electrochemical anodic oxidation. This protocol proceeds in a simple undivided cell by employing LiI or LiBr as redox mediums and halogen sources. A wide range of halogenated N-heterocycles, including three-, five-, and six-membered N-heterocycles were
cyclization cascade process in 43–80% yields. Mechanistic investigations indicated that this reaction may be initiated with the formation of a CF3 radical through anodic single-electron transfer oxidation. The great benefit of this protocol is avoiding the use of metal catalysts and oxidants. More importantly, the late-stage modification of celecoxib and large-scale synthesis have revealed exceptionally
the precatalyst and a cheap silane, (MeO)3SiH, as both the hydrogen-atom donor and the F-atom acceptor, enabling intramolecular/intermolecular hydroaminations of alkenes, two-component carboamination of alkenes, and even three-component carboamination of alkenes. A wide range of valuable aliphatic sulfonamides can be readily prepared using these practical reactions.
Gold-Catalyzed Intramolecular Aminoarylation of Alkenes: CC Bond Formation through Bimolecular Reductive Elimination
作者:William E. Brenzovich、Diego Benitez、Aaron D. Lackner、Hunter P. Shunatona、Ekaterina Tkatchouk、William A. Goddard、F. Dean Toste
DOI:10.1002/anie.201002739
日期:——
Gold‐ilocks and the 3 mol % catalyst: Bimetallic gold bromides allow the room temperature aminoarylation of unactivated terminal olefins with aryl boronic acids using Selectfluor as an oxidant. A catalytic cycle involving gold(I)/gold(III) and a bimolecular reductive elimination for the key CC bond‐forming step is proposed. dppm= bis(diphenylphosphanyl)methane.