Traceless OH-Directed Wacker Oxidation-Elimination, an Alternative to Wittig Olefination/Aldol Condensation: One-Pot Synthesis of <i>α</i>,<i>β</i>-Unsaturated and Nonconjugated Ketones from Homoallyl Alcohols
作者:Venkati Bethi、Rodney A. Fernandes
DOI:10.1021/acs.joc.6b01899
日期:2016.9.16
A new method for one-pot synthesis of β-substituted and β,β-disubstituted α,β-unsaturated methyl ketones from homoallyl alcohols by sequential PdCl2/CrO3-promoted Wacker process followed by an acid-mediated dehydration reaction has been developed. Remarkably, internal homoallyl alcohols delivered regioselectively nonconjugated unsaturated carbonyl compounds under the same protocol. A new starting material-based
Nickel-catalyzed efficient umpolung allylation of ketones with allyliccarbonates in the presence of zinc powder is developed, which accommodates a variety of allylic and ketone substrates. Although chiral ligand is necessary for the transformation, no enantioselectivity was observed. Nickel-catalyzed efficient umpolung allylation of ketones with allyliccarbonates in the presence of zinc powder is developed
The first utility of neodymium as a mediating-metal in the highly [small alpha]-regioselective Barbier reaction of diaryl ketones with allyl halides was reported in this paper. This reaction was conveniently carried...
Facile preparation of allylzinc species from allylboronates and zinc amide via a boron-to-zinc exchange process and their reactions with carbonyl compounds, imines and hydrazones
作者:Yi Cui、Yasuhiro Yamashita、Shū Kobayashi
DOI:10.1039/c2cc34340a
日期:——
Facile formation of allylzinc species from allylboronate and zinc amide was discovered. The boron-to-zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, which were successfully employed in catalytic allylation reactions with electrophiles. Asymmetric catalysis using a chiral zinc amide is also reported.
Catalytic Use of Zinc Amide for Transmetalation with Allylboronates: General and Efficient Catalytic Allylation of Carbonyl Compounds, Imines, and Hydrazones
The efficient catalytic allylation of ketones, imines, and hydrazones with allylboronates using a catalytic amount of zinc amide is reported. In this reaction, the boron‐to‐zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, and the desired allylation reactions proceeded in high efficiency (∼0.1 mol%). A mechanistic study revealed that transmetalation was a rate‐determining