Reaction #57099

Reaction equation

tert-butyl 4-[2-(3-bromophenyl)-2-(1-hydroxycyclohexyl)ethyl]piperazine-1-carboxylate

tributyl(vinyl)tin

→

tert-butyl 4-[2-(1-hydroxycyclohexyl)-2-(3-vinylphenyl)ethyl]piperazine-1-carboxylate

Yield 90.0%

Solvents

toluene

Conditions

Workup

1. 1
   Temperaturewas heated
2. 2
   Temperatureat reflux under nitrogen until all starting material
3. 3
   Otherwas consumed
4. 4
   Otherprecipitation of black palladium
5. 5
   Other(1-2 h)
6. 6
   FiltrationFiltration
7. 7
   Otherthrough Celite® and purification via flash column chromatography (silica, gradient from 0% ethyl acetate/hexane to 10% ethyl acetate/hexane)

Procedure

A mixture of tert-butyl 4-[2-(3-bromophenyl)-2-(1-hydroxycyclohexyl)ethyl]piperazine-1-carboxylate (see Example 135, step 2) (141 mg, 0.300 mmol), tributyl(vinyl)tin (114 mg, 0.360 mmol, 1.2 equivalent), and tetrakis(triphenylphosphine)palladium (17 mg, 0.015 mmol, 5 mol %) in toluene (3 mL) was heated at reflux under nitrogen until all starting material was consumed and precipitation of black palladium occurred (1-2 h). Filtration through Celite® and purification via flash column chromatography (silica, gradient from 0% ethyl acetate/hexane to 10% ethyl acetate/hexane) yielded 111 mg (90%) tert-butyl 4-[2-(1-hydroxycyclohexyl)-2-(3-vinylphenyl)ethyl]piperazine-1-carboxylate as a viscous colorless oil. MS (ES) m/z 415.4 ([M+H]+); HRMS: calcd for C25H38N2O3, 414.2882; found (ESI), 415.2966.

Source