A New Synthetic Method for α-Oxo-β,γ-unsaturated Esters
作者:Hideyuki Sugimura、Kazuhiro Yoshida
DOI:10.1246/bcsj.65.3209
日期:1992.11
α-Oxo-β,γ-unsaturated esters have been prepared in moderate to good yields via a two-step procedure consisting of the boron trifluoride-promoted reaction of 2-(trimethylsiloxy)acrylic esters with acetals, followed by treatment with silica gel in benzene under reflux.
Iodine mediated a simple strategy for the synthesis of β,γ-unsaturated-α-ketoesters and its application for the synthesis of 4,5-dihydropyrazole derivatives
AbstractNovel and efficient method for the synthesis of a series of β,γ-unsaturated-α-ketoesters under mild conditions was developed. This one-step protocol was achieved by the reaction of electron-rich aromatic aldehydes and pyruvates in the presence of 10 mol% of molecular iodine in solvent-free condition at 80 °C temperature. A wide variety of substrates bearing electron releasing groups on aromatic
Palladium-Catalyzed Asymmetric Formal [3+2] Cycloaddition of Vinyl Cyclopropanes and β,γ-Unsaturated α-Keto Esters: An Effective Route to Highly Functionalized Cyclopentanes
作者:Liang-yong Mei、Yin Wei、Qin Xu、Min Shi
DOI:10.1021/om300896z
日期:2012.11.12
Palladium-catalyzed asymmetricformal [3+2] cycloaddition of vinyl cyclopropanes and β,γ-unsaturated α-keto esters proceeded smoothly in the presence of chiral imidazoline–phosphine ligands to give the corresponding highlyfunctionalized cyclopentanes in good yields along with high diastereo- and enantioselectivities under mild conditions.
Rapid Access to Benzoxaphospholes and Their Spiro Analogues by a Three-Component Coupling Involving Arynes, Phosphines, and Activated Ketones
作者:Anup Bhunia、Tony Roy、Rajesh G. Gonnade、Akkattu T. Biju
DOI:10.1021/ol502490t
日期:2014.10.3
multicomponent coupling involving in situ generated arynes from 2-(trimethylsilyl)aryl triflates, phosphines, and various acyclic and cyclic activated carbonylcompounds has been developed. The reaction proceeds via a formal [3 + 2] cycloaddition mode giving access to differently substituted (spiro)benzoxaphosphole derivatives in moderate to good yields. Mild reaction conditions, a broad scope, and the possibility
Enantioselective Organocopper-Catalyzed Hetero Diels–Alder Reaction through <i>in Situ</i> Oxidation of Ethers into Enol Ethers
作者:Ahmet Yesilcimen、Na-Chuan Jiang、Felix H. Gottlieb、Masayuki Wasa
DOI:10.1021/jacs.2c01656
日期:2022.4.13
We demonstrate that a chiral Cu–BOX complex catalyzes the efficient oxidation of ethers into enol ethers in the presence of trityl acetate. Then, the organocopper promotes stereoselective heteroDiels–Alderreaction between the in situ generated enol ethers and β,γ-unsaturated ketoesters, allowing for rapid access to an array of dihydropyran derivatives possessing three vicinal stereogenic centers.