Cyclooctadienes ozonolysis

Muscalure 20, the pheromone of the housefly has been prepared from oleic acid or erucic acid, similarly (Z)-l 1-heneicosene 21, the synergist of muscalure was obtained [189]. The intermediate 22 for the pheromone of the Cabbage looper was prepared using (Z)-methyl-4-octenedioate [166bJ, that was obtained by partial ozonolysis of (Z,Z)-l,5-cyclooctadiene. Similarly disparlure 23, the sex attractant of the gypsy moth, has been synthesized by two successive crossed-couplings with (Z)-4-octene dioate [191],... 

Perhydro-diazocines 28, for the preparation of l,4-diamino-2,3-diol units that are the central structural elements in numerous biomaterials, were obtained from 1,3-cyclooctadiene, by reaction with diethyl azodicarboxylate (DEAD) to give the bridged 1,2-diazocine 103, which by ozonolysis gave the dialdehyde 104 that underwent... 

The first straight-chain A5,9 fatty acid to be synthesized was actually the (5Z,9Z)-5,9-hexacosadienoic acid [47]. The methodology developed by Djerassi et al. is shown in Fig. (17). This six-step synthesis started with the unusual controlled ozonolysis of one of the double bonds of (lZ,5Z)-l,5-cyclooctadiene to secure a 100% Z stereochemistry for what eventually was going to be the A9 double bond of the target molecule. Transformation of the product to the tosylated acetal, followed by Grignard coupling under dilithium tetrachlorocuprate catalysis afforded (Z)-4-heneicosenal, which after Wittig olefination with 4-carboxybutyltriphenylphosphonium bromide resulted in the desired A5,9... 

In the ozonolysis of 1,3-dienes, one double bond often can be cleaved selectively, and in 1,3-cyclodienes, the regioselectivity in fragmentation of the primary ozonide depends upon the size of the rings (eq 13). Eq 13 shows that as the ring size contracts from cyclooctadiene to cyclohexadiene, the a,/3-unsaturated ester becomes favored over the enal. 

The history of polymer science (169,170), takes the reader back to before the macromolecular hypothesis. Natural rubber, civ-polyisoprene, was investigated around the turn of the twentieth century. Morawetz (169) writes of the destructive distillation of rubber to isoprene, and of the ozonolysis of rubber to levulinic aldehyde. These studies led to the dimer ring structure of dimethyl-cyclooctadiene for ds-polyisoprene ... 

---