A stereocontrolled approach to electrophilic epoxides
作者:Otto Meth-Cohn、Clive Moore、Heinrich C. Taljaard
DOI:10.1039/p19880002663
日期:——
Lithium t-butyl hydroperoxide (easily generated by addition of an alkyl-lithium to anhydrous t-butyl hydroperoxide in THF solution) is a powerful reagent for the epoxidation of electrophilic alkenes at –20 to 0 °C under full stereocontrol.
作者:Dimitri Hirsch-Weil、Khalil A. Abboud、Sukwon Hong
DOI:10.1039/c0cc02211j
日期:——
C
1-symmetric isoquinoline-based chiral diaminocarbene ligands (MIQ) have been developed to block three quadrants of the metal coordination sphere, complementing C2-symmetric biisoquinoline-based ligands (BIQ). MIQ-Cu complexes catalyzed conjugate borylation of various α,β-unsaturated amides in good yields (82–99%) and enantioselectivities (75–87% ee).
Allyl-Nickel Catalysis Enables Carbonyl Dehydrogenation and Oxidative Cycloalkenylation of Ketones
作者:David Huang、Suzanne M. Szewczyk、Pengpeng Zhang、Timothy R. Newhouse
DOI:10.1021/jacs.9b02552
日期:2019.4.10
of carbonyl compounds using allyl-nickel catalysis. This development overcomes several limitations of previously reported allyl-palladium-catalyzed oxidation, and is further leveraged for the development of an oxidative cycloalkenylation reaction that provides access to bicycloalkenones with fused, bridged, and spirocyclic ring systems using unactivated ketone and alkene precursors.
Ammonia-borane as a Catalyst for the Direct Amidation of Carboxylic Acids
作者:P. Veeraraghavan Ramachandran、Henry J. Hamann
DOI:10.1021/acs.orglett.1c00591
日期:2021.4.16
Ammonia-borane serves as an efficient substoichiometric (10%) precatalyst for the direct amidation of both aromatic and aliphatic carboxylicacids. In situ generation of amine-boranes precedes the amidation and, unlike the amidation with stoichiometric amine-boranes, this process is facile with 1 equiv of the acid. This methodology has high functional group tolerance and chromatography-free purification
Double Addition of Alkynyllithium Reagents to Amides/Lactams: A Direct and Flexible Synthesis of 3-Amino-1,4-diynes Bearing an Aza-Quaternary Carbon Center
in situ activation of amides with trifluoromethanesulfonic anhydride, followed by doubleaddition of alkynyllithium reagents at a concentration of 0.5 mol·L–1 in dichloromethane. This constitutes an extension of the method of direct reductive bisalkylation of amides that allows both employing alkynyllithium reagents as the first-addition nucleophiles and incorporating an alkynyl group as the first-introduced