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.
Automated structure elucidation of two unexpected products in a reaction of anα,β-unsaturated pyruvate
作者:Gary J. Sharman、Ian C. Jones、Mark P. Parnell、Michael C. Willis、Mary F. Mahon、Dean V. Carlson、Antony Williams、Mikhail Elyashberg、Kirill Blinov、Sergey G. Molodtsov
DOI:10.1002/mrc.1396
日期:2004.7
The reaction between an α,β‐unsaturated pyruvate and ethyl diazoacetate (EDA) yielded two unexpected products. The structures of these products were determined by automated elucidation of the chemical structures using spectroscopic inputs of a series of 1D and 2D NMR data using the computer program ACD/StructureElucidator, StrucEluc. The formation of these products is rationalised. Their structures
DABCO-catalyzed regioselective cyclization reactions of β,γ-unsaturated α-ketophosphonates or β,γ-unsaturated α-ketoesters with allenic esters
作者:Cheng-Kui Pei、Lei Wu、Zhong Lian、Min Shi
DOI:10.1039/c1ob06507f
日期:——
Highly efficient DABCO-catalyzed [4 + 2] cycloaddition of β,γ-unsaturatedα-ketophosphonates or β,γ-unsaturated α-ketoesters with allenicesters gives the corresponding highlyfunctionalized tetrahydropyran and dihydropyran derivatives in good to excellent yields and moderate to good regioselectivities under mild conditions.
The use of beta,gamma-unsaturated-alpha-ketoesters in the intermolecular Stetter reaction furnishes 1,2,5-tricarbonyl compounds in high yield and excellent enantioselectivity. The alpha,delta-diketoesters generated using this methodology serve as useful synthetic building blocks via chemo- and diastereoselective transformations.