Alkynylation of Aldehydes and Ketones Using the Bu<sub>4</sub>NOH/H<sub>2</sub>O/DMSO Catalytic Composition: A Wide-Scope Methodology
作者:Elena Yu. Schmidt、Natalia A. Cherimichkina、Ivan A. Bidusenko、Nadezhda I. Protzuk、Boris A. Trofimov
DOI:10.1002/ejoc.201402275
日期:2014.7
Favorsky reaction of a wide range of aldehydes and ketones with alkynes has been implemented under mild conditions (5–20 °C). Using a Bu4NOH/H2O/DMSO catalytic system, propargylic alcohols are formed cleanly in 39–93 % (mostly 72–93 %) yields and with ca. 100 % selectivity. The method is suitable for aliphatic, aromatic, and heteroaromatic aldehydes and ketones, and for aliphatic, aromatic, and functionalized
The copper-catalyzed reductive Ireland–Claisen rearrangement of propargylic acrylates led to 3,4-allenoic acids. The use of silanes or pinacolborane as stoichiometric reducing agents and triethylphosphite as a ligand facilitated the divergent and complementary selectivity for the synthesis of diastereomeric anti- and syn-rearranged products, respectively. Copper-catalyzed reductive Ireland–Claisen rearrangement
Dehydrative Cp*Co(III)-Catalyzed C–H Bond Allenylation
作者:Malay Sen、Pardeep Dahiya、J. Richard Premkumar、Basker Sundararaju
DOI:10.1021/acs.orglett.7b01415
日期:2017.7.21
unprecedented reactivity of Cp*Co(III) for the synthesis of tetrasubstituted allenes under mild conditions is disclosed. Electron-rich and highly nucleophilic cobalt facilitates the dehydrative C–H bond allenylation directly from propargylic alcohols without any derivatization. The reaction proceeds via reversible cyclometalation followed by alcohol-directed regioselective alkyne insertion and β-hydroxy elimination
The combination of Mo and cationic Au catalysts dramatically accelerated the rearrangement of diverse propargyl alcohols, which includes a short reaction time, mild conditions, and high product yields. A practical application to the highly challenging primary propargyl alcohols and the N-alkynyl amides is achieved.
Alkoxide-Catalyzed Addition of Terminal Alkynes to Ketones