2 Art. 3.— T. Shibata : 



being known clearlj^ as the cis-trans-isomQvs. If the assumption is 

 true that tlie two CO2R groups in the c/s-position exert steric 

 hindrance, while those in the ^/"rt/zi'-position do not, then by the 

 action of the Grignard reagent, camplioric esters should produce 

 campliolides, analogous to the phthalides, while isocamphoric 

 esters should produce glycols or some other non-condensed 

 hydroxyl-clerivatives. 



In fact, this anticipation has been fully confirmed, except in 

 the case of the action of magnesium isoprop}^ iodide on dimethyl 

 camphorate. In this case, a substance has been obtained, which 

 is considered to be a o-ketonic ester having the constitution: 



CH— CH Cü-CH(CH,), * 



CCCHJ, 

 CH,,— C(CH;0— CO-OCHs 



It is known that iso-alkyl groups generally exert a more 

 remarkable steric influence tlian the normal ones (compare M, 

 Davis, Journ. Chem. Soc, 1909, 95, 1397), and it is highly probable 

 that here also the first isopropyl group which has entered into 

 reaction with dimethyl camphorate has hindered the addition of a 

 second molecule of the Geignard reagent, thus producing a ketonic 

 ester, or, in other words, stopping the reaction at its first stage. 



The Action of Magnesium Phenyl Bromide 

 on Dimethyl d-Camphorale. 



d-Camphoric acid, which was prepared by the oxidation of 



* The conipoi-intls of analogous constitution, (j-acyl-benzoic acids, 11 ' , have been 



U-CO.jH 



recently synthesised by the action of the Gbignabd reagent on phthalio acid by H. Simonis and 

 K. Aband (Ber., 1009, 42, 3721), also compare A. Guyot and J. Catel (Bulb Soc. Chim., 1906, 

 [iii], 35, 551). 



