Synthesis of the Skipped Polyene Chain and Its Neighboring Highly Oxygenated Pyran Ring en route to Delivering the C(43)-C(67) Subsector of Amphidinol 3
Development of a Formal [4 + 1] Cycloaddition: Pd(OAc)<sub>2</sub>-Catalyzed Intramolecular Cyclopropanation of 1,3-Dienyl β-Keto Esters and MgI<sub>2</sub>-Promoted Vinylcyclopropane−Cyclopentene Rearrangement
作者:Rockford W. Coscia、Tristan H. Lambert
DOI:10.1021/ja809226x
日期:2009.2.25
A formal [4 + 1] cycloaddition of 1,3-dienyl beta-keto esters has been developed. This two step process involves Pd(II)-catalyzed intramolecular cyclopropanation to produce vinylcyclopropanes and a subsequent mild vinylcyclopropane-cyclopentene rearrangement promoted by MgI(2). The cyclopropanation method notably requires the use of Mg(ClO(4))(2), presumably to facilitate keto-enol tautomerization
Gold-catalyzed intramolecular hydroalkoxylation/cyclization of conjugated dienyl alcohols
作者:B. Chandrasekhar、Jae-Sang Ryu
DOI:10.1016/j.tet.2012.03.120
日期:2012.6
groups to tethered conjugated dienes are described. The reactions proceed smoothly at 60 °C in the presence of 5 mol % of (PPh3)AuCl/AgOTf as a catalyst. A broad range of structurally diverse conjugated dienes produce substituted tetrahydrofurans and tetrahydropyrans in good yields. This reaction represents an atom-economic route to construct five- and six-membered cyclic ethers.
Direct Enantioselective and Regioselective Alkylation of β,γ-Unsaturated Carboxylic Acids with Chiral Lithium Amides as Traceless Auxiliaries
作者:Kai Yu、Bukeyan Miao、Wenqi Wang、Armen Zakarian
DOI:10.1021/acs.orglett.9b00587
日期:2019.3.15
Efficient asymmetric alkylation of β,γ-unsaturated carboxylicacids without prior functionalization is enabled by chiral lithium amides. Enantioselectivity is imparted by a putative mixed lithium amide–enediolate aggregate that acts a traceless auxiliary formed in situ, allowing for a direct asymmetric alkylation and a simple recovery of the chiral reagent.
Cation−π Control of Regiochemistry of Intramolecular Schmidt Reactions en Route to Bridged Bicyclic Lactams
作者:Lei Yao、Jeffrey Aubé
DOI:10.1021/ja068919r
日期:2007.3.1
structures. Not surprisingly, the tendency of these compounds to undergo rapid hydrolysis has complicated their synthesis. Although standard methods for amide bond formation have been used, such routes often proceed in poor yields or are accompanied by difficulty in product isolation.1 In this paper, we describe a solution to the problem of bridged bicyclic lactam synthesis that utilizes the acid-promoted
Synthesis of Medium-Bridged Twisted Lactams via Cation−π Control of the Regiochemistry of the Intramolecular Schmidt Reaction
作者:Michal Szostak、Lei Yao、Jeffrey Aubé
DOI:10.1021/jo902574m
日期:2010.2.19
diazonium cation. This results in the rarely observed rearrangement of the C−C bond distal to the azidoalkyl chain. This reaction pathway also requires the azide-containing tether to be situated in the axial orientation in the key azidohydrin intermediate. Examination of the effect of substitution of aromatic rings on the regiochemistry of the Schmidt reaction shows an increase in the migratory selectivity