Chemistry. — ''Action of Organo-magnesium Compounds on, and 

 Reduction of Cineol." By C. F. van Duin, chem. doets. 

 (Communicated by Prof. P. van Romburgh). 



(Communicated in the meeting of March 31, 1917). 



Tlie first communication in the literature about the action of 

 orga»no-magnesium compounds on internal oxides is given by Blaise ^), 

 who found that on action of RM^r Br on ethylene oxide, both a 

 priraar}' alcohol and the bromic hydrine of glycol are formed. The 

 formation of these two products led him to assume that the organo- 

 magnesium compound is added to part of the oxide according to 

 equation RM.Br + (CHJ, = RCH, - CH,OJVLBr (I) and to another 

 part according to the reaction scheme: RMgBr -\- (CHJ^O = CH^Br — 

 — CH,OMj.R (II). 



Grignard'), however, rightly pointed out that according to Blaise's 

 reaction scheme II the organo-magnesium compound splits up into 

 RMjr and halogen in its addition; a case which had never yet been 

 observed. He then proved that in this first of all an oxonium 



CH.x .MgBr 



compound is formed of the formula O , which on heating 



ch/\r 



CH.OM^Br 



passes into | through an intramolecular conversion. The 



CH,R 

 appearance of the bromic hydrine of the glycol can then also be 

 explained by action of HBr (formed at the hydrolysis of the MgBr'^) 

 on oxide that has not reacted and had then split off. The mechanism 

 of the reaction had been made clear by this. Henry studied the 

 action of organo-magnesium compounds on isobutylene oxide ^), symm. 

 butylene oxide '), and propylene oxide '} ; the first reacts then as the 



1) Blaise. G. R. d. I'Acad. des sciences 134, 551 (1902). 



2) Grignard G. R. d. I'Acad. des sciences 136, 1260 (1903), Bull. Soc. chim. 

 (3) 29, 944 a903). 



8) Henry G. R. de I'Acad. des sciences 145, 21(1907); cf. ibid. 145, J 54 (1907). 



*) Ibid. 145, 406 (1907). 

 5) Ibid. 145, 458 (1907). 



