5 research outputs found
Efficient Benzimidazolidinone Synthesis via Rhodium-Catalyzed Double-Decarbonylative C–C Activation/Cycloaddition between Isatins and Isocyanates
The
first decarbonylative cycloaddition of less-strained cyclic
ketones (isatins) with isocyanates is reported. Initiated by C–C
activation, this distinct [5 – 2 + 2] transformation provides
a rapid entry to access various benzimidazolidinone derivatives, and
a wide range of isocyanates can be efficiently coupled with broad
functional group tolerance. A modified one-pot process combining a
Curtius rearrangement and C–C activation was also achieved
by using acyl azides as the starting materials. A detailed mechanistic
study revealed a surprising double-decarbonylative reaction pathway.
The novel reactivity discovered in this basic research is expected
to shed light on the development of new heterocycle formation methods
through C–C/isocyanate coupling
Efficient Benzimidazolidinone Synthesis via Rhodium-Catalyzed Double-Decarbonylative C–C Activation/Cycloaddition between Isatins and Isocyanates
The
first decarbonylative cycloaddition of less-strained cyclic
ketones (isatins) with isocyanates is reported. Initiated by C–C
activation, this distinct [5 – 2 + 2] transformation provides
a rapid entry to access various benzimidazolidinone derivatives, and
a wide range of isocyanates can be efficiently coupled with broad
functional group tolerance. A modified one-pot process combining a
Curtius rearrangement and C–C activation was also achieved
by using acyl azides as the starting materials. A detailed mechanistic
study revealed a surprising double-decarbonylative reaction pathway.
The novel reactivity discovered in this basic research is expected
to shed light on the development of new heterocycle formation methods
through C–C/isocyanate coupling
Efficient Benzimidazolidinone Synthesis via Rhodium-Catalyzed Double-Decarbonylative C–C Activation/Cycloaddition between Isatins and Isocyanates
The
first decarbonylative cycloaddition of less-strained cyclic
ketones (isatins) with isocyanates is reported. Initiated by C–C
activation, this distinct [5 – 2 + 2] transformation provides
a rapid entry to access various benzimidazolidinone derivatives, and
a wide range of isocyanates can be efficiently coupled with broad
functional group tolerance. A modified one-pot process combining a
Curtius rearrangement and C–C activation was also achieved
by using acyl azides as the starting materials. A detailed mechanistic
study revealed a surprising double-decarbonylative reaction pathway.
The novel reactivity discovered in this basic research is expected
to shed light on the development of new heterocycle formation methods
through C–C/isocyanate coupling
Cobalt-Catalyzed Intramolecular Alkyne/Benzocyclobutenone Coupling: C–C Bond Cleavage via a Tetrahedral Dicobalt Intermediate
A Co(0)-catalyzed
intramolecular alkyne/benzocyclobutenone coupling
through C–C cleavage of benzocyclobutenones is described. Co<sub>2</sub>(CO)<sub>8</sub>/PÂ[3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>]<sub>3</sub> was discovered to be an effective metal/ligand
combination, which exhibits complementary catalytic activity to the
previously established rhodium catalyst. In particular, the C8-substituted
substrates failed in the Rh system, but succeeded with the Co catalysis.
Experimental and computational studies show that the initially formed
tetrahedral dicobalt-alkyne complex undergoes C1–C2 activation
via oxidative addition with Co(0), followed by migratory insertion
and reductive elimination to give the β-naphthol products
Effect of Ring Functionalization on the Reaction Temperature of Benzocyclobutene Thermoset Polymers
The temperature required to induce
cross-linking in typical benzocyclobutene-based
thermosets is near 250 °C, which exceeds the use temperature
of many chemical components. A new and versatile synthesis of BCB-functionalized
monomers has allowed access to monomers that can be incorporated into
a variety of macromolecular platforms to enable significantly reduced
cure temperatures. Incorporation of BCB-functionalized comonomers
in polystyrene and polynorbornene enabled insolublization of thin
films by curing at only 120 °C for 1 h