I. Walden Inversions Involving the Isomeric 2,3-Butanediamenes and Related Compounds. II. An Experimental Test of Kirkwood's Theory of Optical Rotatory Power. III. Zero-Point Vibrational Contributions to the Optical Activity of Isotopically Asymmetric Molecules
<p>It has been demonstrated that reaction of ammonia with 1,2-dimethylethyleneimine is attended by single Walden inversion and that the analogous reaction of ammonia with 2,3-epoxybutane very probably proceeds in the same way. This result and other evidence have been used to assign configu...
| Summary: | <p>It has been demonstrated that reaction of ammonia
with 1,2-dimethylethyleneimine is attended by single Walden
inversion and that the analogous reaction of ammonia with
2,3-epoxybutane very probably proceeds in the same way. This
result and other evidence have been used to assign configurations
to the 3-amino-2-butanols and to draw certain conclusions
about the courses of the reactions in which they are
involved.</p>
<p>Optically active 1,2-dichloropropane has been prepared
and its relative configuration determined. Measurements of
its optical rotatory power in different solvents and at
different temperatures permit an approximate determination of
the optical rotations of the two forms of the molecule
corresponding to the two lowest potential minima for internal
rotation about the 1,2-carbon-carbon bond. These values are
compared with the results of a theoretical calculation; the
resulting assignment of absolute configuration is consistent
with a previous result for 2,3-epoxybutane.</p>
<p>Kirkwood's theory of optical rotation has been modified
so as to take into account contributions arising from zero-point
vibrational effects. The theory is used to calculate
the optical rotations of compounds of the type R<sub>1</sub>R<sub>2</sub>CHD. The
result for α-deuteroethylbenzene is found to be comparable
in magnitude with an experimental value and consistent in
sign with previous assignments of absolute configuration.</p> |
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