Nickel-Catalyzed α-1,3-Dienylation of 1,3-Dicarbonyl Compounds with Propargylic Carbonates
作者:Naoki Ishida、Masahiro Murakami、Yuka Kamino
DOI:10.1055/a-1282-9731
日期:2021.10
Herein reported is a nickel-catalyzed α-1,3-dienylation reaction of 1,3-dicarbonylcompounds with substituted propargylic (e.g., but-2-ynyl) carbonates. The propargyl unit changes into a 1,3-dienyl unit, which is incorporated at the α-position of the 1,3-dicarbonylcompounds.
Here we report the first example of alkyne trifunctionalization through simultaneous construction of C–C, C–O, and C–N bonds via goldcatalysis. With the assistance of a γ-keto directing group, sequential gold-catalyzed alkynehydration, vinyl–gold nucleophilic addition, and gold(III) reductive elimination were achieved in one pot. Diazonium salts were identified as both electrophiles (N source) and
Synthesis of (±)-Gymnomitrol. Mn(OAc)<sub>3</sub>-Initiated Free-Radical Cyclization of Alkynyl Ketones
作者:Steven V. O'Neil、Cheri A. Quickley、Barry B. Snider
DOI:10.1021/jo9622338
日期:1997.4.1
Mn(OAc)(3)-initiated cyclization of alkynyl ketones in 9-19:1 EtOH/HOAc at 90 degrees C is a useful cyclization procedure in favorable cases. Cyclization of (trimethylsilyl)alkynyl ketone 4e provides 62% of silylalkenes 26 and 27 in the key reaction of a seven-step (16% overall yield) synthesis of gymnomitrol (1) from readily available ketone 23. 9alpha-Hydroxygymnomitryl acetate (2) and 9-oxogymnomitryl
Bicyclo[m.n.1]alkenone frameworks possessing quaternary carbon centers adjacent to a bridged ketone are frequently found in bioactive natural products. Although several methods have been developed to construct such frameworks, most of them are specific to a particular scaffold. Herein, we report a mild and highly efficient method to generate carbon-bridged frameworks of various sizes using phosphino gold(I) catalysts.
Rhodium-catalyzed arylative cyclization of alkynones induced by addition of arylboronic acids
Alkynones react with arylboronic acids in the presence of a rhodium(I) catalyst to afford four- and five-membered-ring cyclic alcohols equipped with a tetrasubstituted exocyclic olefin. The cyclic allylic alcohol skeleton is constructed by the carbon-carbon bond formation between the carbonyl group and an alkenylrhodium(I) intermediate formed by the regioselective addition of an arylrhodium(I) species across the carbon-carbon triple bond. (c) 2007 Elsevier Ltd. All rights reserved.