18 



FATTY ACID METABOLISM IN MICROORGANISMS 



reduced with hydrazine to give an intermediate of structure 

 (IV). 



Elongation of the carboxyl end of intermediate (IV) (Fig. 

 1.11) is effected according to a scheme which was developed 

 by Stallberg-Stenhagen (21). Identity of the synthetic com- 

 pound (x and y = 7) with dihydrosterculic acid unequivo- 

 cally establishes the structure of this compound as Di.-cis- 

 9,10-methyleneoctadecanoic acid. DL-c/5-ll,12-Methylene- 

 octadecanoic acid (DL-lactobacillic acid) is synthesized from 

 cyclopropane diacetic acid by the same procedures. 



Addition of iodomethyl zinc iodide across the double 

 bond of olefins affords cis cyclopropane derivatives in high 

 yield (28). This reaction has served to synthesize dihydro- 



CH2 



CH2 



(H) 



Oxidation 



"v" 



Ni, H,,OH- 



f 



Br Br 



HOOC— CH2 CH2— COOH HOOC— CH2 CH2— COOH 



(IV) (III) 



Fig. 1.9. Stereospecific synthesis o£ c/5-cyclopropane-l,2-diacetic acid. 



