Chemistry. — On the determination of the configuration of cyclic 
cis and trans diols and the rearrangements of atoms and 
groups of atoms during chemical reactions’. By Prof. J. BöESEKEN 
and Car. van Loon. 
(Communicated at the meeting of June 28, 1919) 
In former communications in which the configuration of the 
hydrindene diols was discussed, we called attention to the fact that 
indene oxide, when being hydrated, may yield the cis diol as well as 
the trans diol. In the meantime we ascertained that the quantities 
formed of these diols depend on the reaction of the medium, the 
formation of the trans compound is favoured by alkaline media. 
Considering the probable situation of the atoms in indene oxide, 
the generation of trans diol deserves close attention ; one might expect 
the cis compound: 
OH OH 
H 
ip H 
Now it was of high importance to determine the configuration of 
the two diols with ful! certainty. Unfortunately the classic method, 
by testing the resolvability into optical antipodes, is of no avail 
here as both diols are asymmetric and consequently resolvable, so that 
another method had to be looked for. 
We have already proved that of the two diols only one increases 
the conductivity of boric acid and we have deemed ourselves justified 
in assigning to this diol the cis configuration — rightly, as will be 
proved below. 
[Here I may take it to be known, that the increase of the acid 
properties of boric acid by a number of substances, is due to the 
formation of complex dissociable compounds ; these are formed especially 
if two hydroxy] groups are situated “favourably” in regard to boric acid. | 
As this sole argument depends on the efficiency of the boric acid 
method, it called for a confirmation which could be given by our 
investigation on the cyclapentane diols. 
