Diphenylethylenediamine

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Diphenylethylenediamine
Dpen.png
Names
Preferred IUPAC name
1,2-Diphenylethane-1,2-diamine
Other names
1,2-Diphenyl-1,2-diaminoethane
DPEN
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.127.996
Properties
C14H16N2
Molar mass 212.29 g/mol
Appearance White crystals
Melting point 79 to 83 °C (174 to 181 °F; 352 to 356 K)
Slightly
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

1,2-Diphenyl-1,2-ethylenediamine is an organic compound with the formula H2NCHPhCHPhNH2, where Ph is C6H5, phenyl. This diamine is a precursor to a ligand for certain homogeneous hydrogenation catalysts. It can be prepared from benzil by reductive amination.[1]

Optical resolution[edit]

DPEN can be obtained as both the chiral and meso diastereomers, depending on the relative stereochemistry of the two CHPhNH2 subunits. The chiral diastereomer, which is of greater value, can be resolved into the R,R- and S,S- enantiomers using tartaric acid as the resolving agent. In methanol, the R,R enantiomer has a specific rotation of [α]23 +106±1°.

TsDPEN[edit]

N-tosylated derivative, TsDPEN, is a ligand precursor for catalysts for asymmetric transfer hydrogenation. For example, (cymene)Ru(S,S-TsDPEN) catalyzes the hydrogenation of benzil into (R,R)-hydrobenzoin. In this reaction, formate serves as the source of H2:[2][3]

PhC(O)C(O)Ph + 2 H2 → PhCH(OH)CH(OH)Ph (R,R isomer)

This transformation is an example of desymmetrization, the symmetric molecule benzil is converted to the dissymmetric product.

Applications[edit]

DPEN and BINAP are the key ingredients of Noyori's 2nd Generation Ruthenium based chiral hydration catalyst, Ryōji Noyori earned the Nobel Prize in 2001.

References[edit]

  1. ^ S. Pikul, E. J. Corey (1998). "(1R,2R)-(+)- and (1S,2S)-(−)- 1,2-Diphenyl-1,2-Ethylenediamine". Organic Syntheses. ; Collective Volume, 9, p. 387 
  2. ^ Takao Ikariya, Shohei Hashiguchi, Kunihiko Murata, and Ryōji Noyori (2005). "Preparation of Optically Active (R,R)-Hydrobenzoin from Benzoin or Benzil". Organic Syntheses: 10. 
  3. ^ Fei Chen; Zi-Yuan Ding; Yan-Mei He; Qing-Hua Fan (2015). "Synthesis of Optically Active 1,2,3,4-Tetrahydroquinolines via Asymmetric Hydrogenation Using Iridium-Diamine Catalyst". Org. Syn. 92: 213. doi:10.15227/orgsyn.092.0213.