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Nuclear Magnetic Resonance Studies of Some 1,1-Difluoro-3-Phenylcyclobutane Derivatives


Takahashi, Masaaki (1962) Nuclear Magnetic Resonance Studies of Some 1,1-Difluoro-3-Phenylcyclobutane Derivatives. Master's thesis, California Institute of Technology. doi:10.7907/481A-5Q94.


1-Difluoro-2, 2-dichloro-3-methy1-3-phenylcyclobutane has been prepared by the cycloacidition of a-methylstyrene to 1,1-difluoro2, 2-dichloroethylene. A 2 cps long-range H-F spin-spin coupling has been observed over five consecutive saturated bonds in 1,1-difluoro2, 2-dichloro-3-methyl-3-phenylcyclobutane, involving one of the fluorines at the 1-position and the protons of the 3-methyl group. Analysis of the spectrum and that of the stereospecifically labeled 4-deutero derivatives suggest that the fluorine involved is the one cis to the methyl group. The n. m. r. studies of 1,1-difluoro-3-bromo-3-phenylcyclobutane which was obtained by bromination of 1,1-difluoro-3-phenylcyclobutane with N-bromosuccinimide indicate that this molecule has on the average a more nearly planar cyclobutane ring than that of 1,1- difluoro-2, 2-dichloro-3-methyl-3-phenylcyclobutane. The four protons of the 2- Etna 4-positions are nearly magnetically equivalent, so that the spectrum of this compound is almost that of an ABX_4 system rather than an ABX_2Y_2 system. The theoretical calculations suggest that the chemical shift difference between X and Y is on the order of 1-2 cps. The chemical shift difference between the fluorines decreases in 1,1-difluoro-2, 2-dichloro-3-methy1-3-phenylcyclobutane and 1,1- difluoro-3-bromo-3-phenylcyclobutane with increasing temperature, suggesting that rapid ring-inversion is taking place.

Item Type:Thesis (Master's thesis)
Subject Keywords:(Chemistry)
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemistry
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Roberts, John D.
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 January 1962
Record Number:CaltechTHESIS:05062010-112117806
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5777
Deposited By: Tony Diaz
Deposited On:10 Aug 2010 18:33
Last Modified:21 Dec 2023 21:58

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