Phosphorus cyclopropane derivatives

A small number of publications have been concerned with phosphorus-cyclopropane derivatives. The state of oxidation of the phosphorus is important, as is the valency and it is as yet difficult to form an overall picture. 

Treatment of cyclopropyl ketones with phosphorus pentachloride afforded (1,1-dichloroal-kyl)cyclopropane derivatives in variable yield. ss-iass jjjg reaction can be hampered by ring opening if the reaction is performed above room temperature. Thus, treatment of phenyl 1 -phenylcyclopropyl ketone with phosphorus pentachloride in carbon tetrachloride gave l-[dichloro(phenyl)methyl]-l-phenylcyclopropaneas the sole product at ambient temperature, whereas a second product, l,4-dichloro-l,2-diphenylbut-l-ene, was formed in addition at reflux temperature. ... 

Phosphorus triiodide or diphosphorus tetraiodide/triethylamine at 20 °C (Scheme 43) carbonyl diimidazole or thiocarbonyl diimidazole/toluene at 110 °C, (Scheme 44) however, cleanly provide 87) alkylidene cyclopropanes from methylseleno derivatives. The best results are obtained with the first reagent for those (P-hydroxy-alkyl-methylselenides derived from aldehydes (Scheme 42) whereas PI3/NEt3 works parti-... 

Fused cyclopropanes are obtained by intramolecular cyclopropanations or by intermolecular reactions with cyclic alkenes or aromatic derivatives. The phosphoryl carbenes are the only phosphorus-substituted carbenes used in these reactions. 

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