TY - JOUR

T1 - Iridium‐Catalyzed Condensation of Amines and Vicinal Diols to Substituted Piperazines

A1 - Lorentz-Petersen,Linda Luise Reeh

A1 - Nordstrøm,Lars Ulrik Rubæk

A1 - Madsen,Robert

AU - Lorentz-Petersen,Linda Luise Reeh

AU - Nordstrøm,Lars Ulrik Rubæk

AU - Madsen,Robert

PB - Wiley - V C H Verlag GmbH & Co. KGaA

PY - 2012

Y1 - 2012

N2 - <p>A straightforward procedure is described for the synthesis of piperazines from amines and 1,2‐diols. The heterocyclization is catalyzed by [Cp*IrCl₂]₂ and sodium hydrogen carbonate and can be achieved with either toluene or water as solvent. The transformation does not require any stoichiometric additives and only produces water as the byproduct. The reaction can be performed between a 1,2‐diamine and a 1,2‐diol or by a double condensation between a primary alkylamine and a 1,2‐diol. At least one substituent is required on the piperazine ring to achieve the cyclization in good yield. The mechanism is believed to involve dehydrogenation of the 1,2‐diol to the α‐hydroxy aldehyde, which condenses with the amine to form the α‐hydroxy imine. The latter rearranges to the corresponding α‐amino carbonyl compound, which then reacts with another amine followed by reduction of the resulting imine.</p>

AB - <p>A straightforward procedure is described for the synthesis of piperazines from amines and 1,2‐diols. The heterocyclization is catalyzed by [Cp*IrCl₂]₂ and sodium hydrogen carbonate and can be achieved with either toluene or water as solvent. The transformation does not require any stoichiometric additives and only produces water as the byproduct. The reaction can be performed between a 1,2‐diamine and a 1,2‐diol or by a double condensation between a primary alkylamine and a 1,2‐diol. At least one substituent is required on the piperazine ring to achieve the cyclization in good yield. The mechanism is believed to involve dehydrogenation of the 1,2‐diol to the α‐hydroxy aldehyde, which condenses with the amine to form the α‐hydroxy imine. The latter rearranges to the corresponding α‐amino carbonyl compound, which then reacts with another amine followed by reduction of the resulting imine.</p>

KW - Alcohols

KW - Amination

KW - Cyclization

KW - Homogeneous catalysis

KW - Nitrogen heterocycles

U2 - 10.1002/ejoc.201201099

DO - 10.1002/ejoc.201201099

JO - European Journal of Organic Chemistry

JF - European Journal of Organic Chemistry

SN - 1434-193X

IS - 34

VL - 2012

SP - 6752

EP - 6759

ER -