trans-2-Phenyl-1-cyclohexanol

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Skeletal formula of the (1S,2R) enantiomer of trans-2-Phenyl-1-cyclohexanol
Skeletal formula of the (1S,2R) enantiomer of trans-2-Phenyl-1-cyclohexanol

trans-2-Phenyl-1-cyclohexanol is an organic compound. The two enantiomers of this compound are used in organic chemistry as chiral auxiliaries.

[edit] Preparation

The enantioselective synthesis was accomplished by J. K. Whitesell by adding Pseudomonas fluorescens lipase to racemic trans-2-phenylcyclohexyl chloroacetate.[1][2] This enzyme is able to hydrolize the ester bond of the (-) enantiomer but not the (+) enantiomer. The (-)-cyclohexanol and the (+)-ester are separated by fractional crystallization and the isolated (+)-ester hydrolyzed to the (-)-cyclohexanol in a separate step.

The enantiomers have also been prepared by the Sharpless asymmetric dihydroxylation of 1-phenylcyclohexene to the diol followed by the selective reduction of the 1-hydroxyl group by Raney nickel.[3]

trans-2-Phenyl-1-hexanol enantiomers in chair conformations
trans-2-Phenyl-1-hexanol enantiomers in chair conformations


[edit] References

  1. ^ J. K. Whitesell, H. H. Chen and R. M. Lawrence (1985). "trans-2-Phenylcyclohexanol. A powerful and readily available chiral auxiliary". J. Org. Chem. 50 (23): 4663–4664. doi:10.1021/jo00223a055. 
  2. ^ A. Schwartz, P. Madan, J. K. Whitesell, and R. M. Lawrence (1993). "Lipase-Catalyzed Kinetic Resolution of Alcohols via Chloroacetate Esters: (−)-(1R,2S)-Trans-2-Phenylcyclohexanol And (+)-(1S,2R)-Trans-2-Phenylcyclohexanol". Org. Synth.; Coll. Vol. 8: 516. 
  3. ^ Javier Gonzalez, Christine Aurigemma, and Larry Truesdale (2004). "Sharpless bishydroxylation procedure to trans-2-phenyl-1-cyclohexanol". Org. Synth.; Coll. Vol. 10: 603.