Nickel-catalyzed hydrocarboxylation of ynamides with CO<sub>2</sub> and H<sub>2</sub>O: observation of unexpected regioselectivity
作者:Ryohei Doi、Iman Abdullah、Takahisa Taniguchi、Nozomi Saito、Yoshihiro Sato
DOI:10.1039/c7cc03127k
日期:——
α-amino-α,β-unsaturated esters with high regioselectivities. The selective α-carboxylation of ynamides with this catalytic protocol is unexpected in view of the electronic bias of ynamides and is in sharp contrast to our previous study in which a stoichiometric amount of Ni(0) was used to form a β-carboxylated product exclusively. We revealed that this unexpected C–C bond formation was induced by the
A metal-free formal [2 + 2 + 2] cycloaddition of functionalized ynamide–nitriles with ynamides is disclosed which offers highly efficient access to polysubstituted δ-carboline derivatives under the mediation of TfOH. This strategy is highly regioselective and chemoselective and displays mild conditions, high yields, and efficiency (within 1 min) in addition to substrates scopes (56 examples).
Site-specific introduction of gold-carbenoids by intermolecular oxidation of ynamides or ynol ethers
作者:Paul W. Davies、Alex Cremonesi、Nicolas Martin
DOI:10.1039/c0cc02736g
日期:——
Ynamides and ynol ethers undergo intermolecular gold-catalysed reaction with a nucleophilic oxidant to access metal-carbenoid reactivity patterns. A site-specific oxidation/1,2-insertion cascade is used for a general access to functionalised α,β-unsaturated carboxylic acid derivatives and vinylogous carbimates.
Visible Light-Mediated Copper(I)-Catalysed Aerobic Oxidation of Ynamides/Ynamines at Room Temperature: A Sustainable Approach to the Synthesis of α-Ketoimides/α-Ketoamides
aerobic oxidation of the C≡C bond in ynamides/ynamines at room temperature by using molecular oxygen as an oxidant is described. Overall, 23 examples were demonstrated with substrates having a wide range of functional groups. The current protocol can be readily scaled up to a preparative (1–2 g) scale with high yields (78–92%), high atom efficiency, and reaction mass efficiency. The mechanistic study shows
A radical chain isomerization of N-sulfonyl ynamides to isolable ketenimines is developed, featuring mild reaction conditions, a high efficiency, ∼100% atom economy, a broad substrate scope, and column chromatography-free workup in most cases. Meanwhile, an unprecedented dearomatization of furans is achieved by the radical chain isomerization-triggered aza-Claisen rearrangement, providing highly chemo-