5 research outputs found
Formation of Five- and Seven-Membered Rings Enabled by the Triisopropylsilyl Auxiliary Group
A highly convenient synthetic pathway to 2-indanones from aldehydes was established. The introduction of a triisopropylsilyl group greatly facilitated Meinwald rearrangement of the intermediate epoxides and alleviated the necessity of polysubstitution for the clean formation of indenes and cyclopentadienes via cyclodehydration of allylic alcohols; unprecedented freedom with respect to the product structure was thus achieved. The developed methodology could also be applicable to the formation of seven-membered rings leading to dibenzo[7]annulenes and dibenzosuberones
Dichotomy of Atom-Economical Hydrogen-Free Reductive Amidation vs Exhaustive Reductive Amination
Rh-catalyzed
one-step reductive amidation of aldehydes has been
developed. The protocol does not require an external hydrogen source
and employs carbon monoxide as a deoxygenative agent. The direction
of the reaction can be altered simply by changing the solvent: reaction
in THF leads to amides, whereas methanol favors formation of tertiary
amines
Ruthenium-Catalyzed Reductive Amination without an External Hydrogen Source
A ruthenium-catalyzed
reductive amination without an external hydrogen
source has been developed using carbon monoxide as the reductant and
rutheniumÂ(III) chloride (0.008–2 mol %) as the catalyst. The
method was applied to the synthesis of antianxiety agent ladasten
Atom- and Step-Economical Preparation of Reduced Knoevenagel Adducts Using CO as a Deoxygenative Agent
A highly efficient
one-step Rh-catalyzed preparation of reduced
Knoevenagel adducts of various aldehydes and ketones with active methylene
compounds has been developed. The protocol does not require an external
hydrogen source and employs carbon monoxide as a deoxygenative agent.
The use of malonic acid or cyanoacetamide enabled efficient formal
deoxygenative addition of methyl acetate or acetonitrile to aldehydes.
The developed methodology was applied to the synthesis of the precursors
of biomedically important compounds
Cyclobutadiene Metal Complexes: A New Class of Highly Selective Catalysts. An Application to Direct Reductive Amination
A catalyst
of a new type, cyclobutadiene complex [(C<sub>4</sub>Et<sub>4</sub>)ÂRhÂ(<i>p</i>-xylene)]ÂPF<sub>6</sub>, was
found to promote selective reductive amination in the presence of
carbon monoxide under mild conditions (1–3 bar, 90 °C).
The reaction demonstrated perfect compatibility with a wide range
of functional groups prone to reduction by conventional reducing agents.
The developed system represents the first systematic investigation
of cyclobutadiene metal complexes as catalysts