\ 



459 



901. Traas, P. C; Boelens, H.; and Takken, H. J. 1976. Convenient synthesis 

 of 3,3-dimethylcyclohexylideneacetaldehyde, a sex attractant of the male 

 boll weevil. Synth. Commun. 6: 489-493. 



In a previous communication we reported on the synthesis of 3, 3-dimethylcyclo- 

 hexylideneacetaldehyde, an importaut component of the sex pheromone complex 

 of the male boll weevil. A key step in this synthesis involved the simultaneous 

 removal of halogen and a double bond from an intermediate poly unsaturated 

 aldehyde by selective reduction. As a part of our Investigations on the 

 Vllsmeier formylation of vinylcyclopropanes and dienes , we have found an easy 

 route to aldehyde, and we now show that this aldehyde can serve as an excellent 

 synthon for the preparation of 3, 3-dimethylcyclohexylideneacetaldehyde. 



902. Trost, B. M. ; Keeley, D. E.; Arndt, H. C; and Bogdanowicz, M. J. 1977. 

 New synthetic reactions, synthesis of cyclobutanes, cyclobutenes, and 

 cyclobutanones. Applications in geminal alkylatlon. J. Am. Chera. Soc. 

 99: 3088-3100. 



The chemistry of the adducts of 1-lithiocyclopropyl phenyl sulfide to aldehydes 

 and ketones is reported. Treatment of these compounds with £-toluenesulfonic 

 acid under anhydrous conditions or the Burgess reagent yields 1-phenylthio- 

 cyclobutenes, which may be hydrolyzed to cyclobutanones, desulfurized to cyclo- 

 butanes, or thernvalized to dienes. Rearrangement to cyclobutanones can be 

 achieved under four sets of conditions: (1) aqueous fluoboric acid-ether, (2) 

 stannic chloride-methylene chloride, (3) £-toluenesulfonic acid in benzene 

 saturated with water, and (4) Meerwein's reagent. Alternatively, the 0- 

 phenylene phosphite ester of these alcohols, generated by directly quenching 

 the reaction of 1-lithiocyclopropyl phenyl sulfide and the carbonyl compound 

 with £-phenylene phosphorochlorodite, rearranges to the cyclobutanone in re- 

 fluxing aqueous THF in the presence of an acid catalyst. The stereochemistry 

 of this arrangement is delineated and complements that obtained by the cyclo- 

 butanone annelation with dephenylsulfonium cyclopropylidc. The approach allows 



