- Spectroscopic and X-ray crystallographic evidence for electrostatic effects in 4-substituted cyclohexanone-derived hydrazones, imines, and corresponding salts
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The axial conformer of several 4-substituted cyclo-hexanone hydrazone salts was found to predominate in solution. Changes in the charge of the molecule and the polarity of the solvent led to changes in the conformational preference of each molecule that were consistent with electrostatic stabilization of the axial conformer. H NMR spectroscopic analysis was utilized to determine the structure of cyclohexanone-derived substrates by comparison to conformationally restricted trans-decalone derivatives and computational models. X-ray crystallography demonstrated that the axial configuration of a pendant benzyloxy group is the preferred conformation of an iminium ion in the solid state. The structure of a neutral hydrazone was also determined to favor the axial configuration for a pendant benzyloxy group in the solid state.
- Dibble, David J.,Ziller, Joseph W.,Woerpef
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p. 7706 - 7719
(2011/12/02)
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- The Chemical and Electrochemical Reductions of 5-Bromodecalone and 4-Bromodecalone
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5-Bromodecalone (1) was prepared by the reaction of potassium bromide in acetonitrile on (4aα,5α,8aβ)-5-tosyloxyoctahydronaphthalen-1(2H)-one (15) with apparent retention of configuration.It was also prepared by hydrogen bromide cleavage of (3aRS,3bRS,7aRS)-octahydro-7H-cyclopentacyclopropabenzen-7-one (17).On reaction with sodium potassium alloy ketone (1) gives α-decalone (33) and ketone (17) as the principal products whereas reduction with tributylstannane gives only ketone (33).Electrochemical reduction of ketone (1) gives trans-cyclodec-5-en-1-one (3) as well as ketones (17) and (33). 4-Bromodecalone (2) was prepared from (4α,4aα,8aβ)-4-tosyloxyoctahydronaphthalen-1(2H)-one (29), by the reaction with potassium bromide in acetonitrile, with inversion of configuration.Electrochemical reduction of ketone (2) gives trans-1-acetyl-2-vinylcyclohexane (36), α-decalone (33), (E)-cyclodec-4-en-1-one (4) and (1aRS,1bSR,5aRS,6aRS)-octahydrocyclopropainden-6(6aH)-one (24).
- Hamon, David P. G.,Richards, Kenneth R.
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p. 2243 - 2259
(2007/10/02)
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