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Buchwald–Hartwig amination: Ethyl 4-bromobenzofuran-2-carboxylate → tert-Butyl 4-(2-(ethoxycarbonyl)benzofuran-4-yl)piperazine-1-carboxylate

46% yield, run at 95 °C, as recorded by experimental reaction archive. The written procedure is below.

verified record, 46% yield recorded, Not balanced as written, From experimental reaction archive

Reagents, catalysts and solvents are in the table below.

The atoms, from reactants to products

CCOCOCCCCNCCNCOOCCCCCCCCCCOBr
Reactants · 1/6
breakingformingbond order changesmapped atom that changes

Drawn from the record's atom map: which bonds break and which form between the reactants and products the source listed. It shows a change in connectivity, not a simulated trajectory and not a mechanism.

What was in the flask

RoleSpeciesFormulaYield
ReactantEthyl 4-bromobenzofuran-2-carboxylateC₁₁H₉BrO₃—
Reactanttert-Butyl piperazine-1-carboxylateC₉H₁₈N₂O₂—
ReagentCesium carbonateCCs₂O₃—
Catalyst2-Dicyclohexylphosphino-2',4',6'-triisoprophylbiphenylC₃₃H₄₉P—
CatalystBis(dibenzylideneacetone)palladiumC₅₁H₄₂O₃Pd₂—
Solvent1,4-DioxaneC₄H₈O₂—
Producttert-Butyl 4-(2-(ethoxycarbonyl)benzofuran-4-yl)piperazine-1-carboxylateC₂₀H₂₆N₂O₅45.92%

The equation does not balance as written. That is usual for an experimental record: the source listed what it put in and what it measured, not a stoichiometric equation.

Conditions

Temperature
95 °C

Only the dimensions the source stated are listed. Anything absent here was not recorded, and it is not inferred from what the class usually needs.

Yield

  • 46% of tert-Butyl 4-(2-(ethoxycarbonyl)benzofuran-4-yl)piperazine-1-carboxylate.

Procedure

Copied from the source record, unedited

ethyl 4-bromobenzofuran-2-carboxylate (7.7 g, 28.61 mmol), tert-butyl piperazine-1-carboxylate (5.33 g, 28.61 mmol), Tris(dibenzylideneacetone)dipalladium(0) (1.310 g, 1.43 mmol), 2-Dicyclohexylphosphino-2',4',6'-tri-iso-propyl-1,1'-biphenyl (1.364 g, 2.86 mmol) and CESIUM CARBONATE (12.12 g, 37.20 mmol) in dioxane (40 mL) was heated under argon to 95 °C overnight. The mixture was allowed to cool. The mixture was diluted with EtOAc and the mixture was filtered through a pad of Celite. The filterate was collected and the solvent was removed by rotary evaporation. The crude product was added to a silica gel column and was eluted with 0-50% EtOAc in heptane. The collected fractions were combined and the solvent was removed to yield tert-butyl 4-(2-(ethoxycarbonyl)benzofuran-4-yl)piperazine-1-

The source

This record comes from experimental reaction archive (ord-a752f4a96bed42979fc54c8d98f05186). Open the source and check it against what is on this page.

  • experimental reaction archive record ord-a752f4a96bed42979fc54c8d98f05186 from dataset "750 AstraZeneca ELN dataset" (url: https://chemrxiv.org/engage/chemrxiv/article-details/60c9e3f37792a23bfdb2d471). No atom mapping is provided by the source.

    experimental record · quality medium · source

experimental reaction record.

How to read this record

This is one experiment, not a rule. It says that on one occasion these species were combined under these conditions and this came out. It does not say the reaction will give the same result on your substrate, and nothing on the page has been generalised into a claim that it would.

The pathway is a separate question, kept on separate pages. A mechanism here is the canonical arrow pushing for a class, run on real structures and labelled rule-derived. It is not evidence, and this record is not a mechanism.