Selective reduction of alkynes to cis-alkenes by hydrometallation using [(Ph3P)CuH]6.
作者:John F. Daeuble、Colleen McGettigan、Jeffrey M. Stryker
DOI:10.1016/s0040-4039(00)97371-4
日期:1990.1
Selective reduction of alkynes to the corresponding alkenes is reported using the stable, readily prepared copper(I) hydride reagent, [(Ph3P)CuH]6. Terminal alkynes are reduced at room temperature, unactivated internal alkynes react only at elevated temperature. Disubstituted alkynes with propargyl activation are also reduced, giving cis-olefins selectively. Protection of propargylic alcohol functionality
Improvements and Applications of the Transition Metal-Free Asymmetric Allylic Alkylation using Grignard Reagents and Magnesium Alanates
作者:David Grassi、Alexandre Alexakis
DOI:10.1002/adsc.201500495
日期:2015.10.12
Two new N-heterocyclic carbene (NHC) ligands have been synthesized and employed in the transition metal-free asymmetric allylic alkylation (AAA) mediated by Grignardreagents and magnesium alanates. The employment of these ligands showed high yields and improved regio- and enantioselectivity in the formation of tertiary and quaternary stereocenters. Moreover, the low catalyst loading (up to 0.3 mol%)
Regioselective and Stereospecific Rhodium-Catalyzed Allylic Cyanomethylation with an Acetonitrile Equivalent: Construction of Acyclic β-Quaternary Stereogenic Nitriles
作者:Mai-Jan Tom、P. Andrew Evans
DOI:10.1021/jacs.0c02316
日期:2020.7.15
A highlyregioselective and stereospecific rhodium-catalyzed cyanomethylation of tertiary allyliccarbonates for the construction of acyclic β-quaternary stereogenic nitriles is described. This protocol represents the first example of a metal-catalyzed allylicsubstitution reaction using a triorganosilyl-stabilized acetonitrile anion, which permits access to several carbonyl derivatives that are challenging
Enantioselective Construction of All-Carbon Quaternary Centers by Branch-Selective Pd-Catalyzed Allyl–Allyl Cross-Coupling
作者:Ping Zhang、Hai Le、Robert E. Kyne、James P. Morken
DOI:10.1021/ja2039248
日期:2011.6.29
The Pd-catalyzed cross-coupling of racemic tertiary allylic carbonates and allylboronates is described. This reaction generates all-carbonquaternarycenters in a highly regioselective and enantioselective fashion. The outcome of these reactions is consistent with a process that proceeds by way of 3,3'-reductive elimination of bis(η(1)-allyl)palladium intermediates. Strategies for distinguishing the
The formation of one unavoidable byproduct in traditional disproportionationreactions limits their applications in synthesis. Inspired by convergent disproportionation, we develop an iodine-induced cyclization and oxidation of allylic alcohols to produce highly functionalized bicyclo[3.2.1]octanes through creation of six new bonds. Guided by the mechanism, we elaborated a variety of other bicyclo[3