Hydrophobic, low-loading and alkylated polystyrene-supported sulfonic acid for several organic reactions in water: remarkable effects of both the polymer structures and loading levels of sulfonic acidsElectronic supplementary information (ESI) available: Experimental details. See http://www.rsc.org/suppdata/ob/b3/b305622h/
Site-Selective Mono-Oxidation of 1,2-Bis(boronates)
作者:Lu Yan、James P. Morken
DOI:10.1021/acs.orglett.9b01204
日期:2019.5.17
Site-selective oxidation of vicinal bis(boronates) is accomplished through the use of trimethylamineN-oxide in 1-butanol solvent. The reaction occurs with good efficiency and selectivity across a range of substrates, providing 2-hydro-1-boronic esters which are shown to be versatile intermediates in the synthesis of chiral building blocks.
Last‐minute deal: A directlactonisation of ethers and alcoholsontoamides that proceeds at room temperature under mild conditions is reported (see scheme). This allows the effective saving of up to two unproductive, sequential deprotection operations in synthetic sequences. Mechanistic studies are described, and a new “amidestrategy” that exploits the dual robustness/late‐stage selective activation
Modular Monodentate Oxaphospholane Ligands: Utility in Highly Efficient and Enantioselective 1,4-Diboration of 1,3-Dienes
作者:Christopher H. Schuster、Bo Li、James P. Morken
DOI:10.1002/anie.201102404
日期:2011.8.16
Tune it up! Tunable, chiral, monodentateoxaphospholaneligands (termed OxaPhos) are highly effective in the Pt‐catalyzed title reaction, providing the 1,4‐addition products in enantiomer ratios approaching 99:1 (see scheme). In the presence of enantiomerically pure cis‐iBu‐OxaPhos, a catalyst loading of only 0.02 mol % [Pt(dba)3] was sufficient for effective reaction. pin=pinacolato, dba=dibenzylideneacetone
Controlling Selectivity in Alkene Oxidation: Anion Driven Epoxidation or Dihydroxylation Catalysed by [Iron(III)(Pyridine‐Containing Ligand)] Complexes
A highly reactive and selective catalytic system comprising Fe(III) and macrocyclic pyridine‐containing ligands (Pc‐L) for alkene oxidation by using hydrogen peroxide is reported herein. Four new stable iron(III) complexes have been isolated and characterized. Importantly, depending on the anion of the iron(III) metal complex employed as catalyst, a completely reversed selectivity was observed. When
Ring-Opening Reactions of Epoxides Catalyzed by Molybdenum(VI) Dichloride Dioxide
作者:Dillip Chand、Kandasamy Jeyakumar
DOI:10.1055/s-2008-1032163
日期:2008.3
alcohols, acetonides, and α-alkoxy ketones is achieved by using molybdenum(VI) dichloride dioxide (MoO 2 Cl 2 ) as a catalyst. Alcohol, aldehyde, oxime, tosyl, and TERT-butyldimethylsilyl functional groups are tolerated during the methanolysis and acetonidation of the functionalized epoxides. No polymerization product is observed with any of the epoxides. Direct conversion of epoxides devoid of sensitive