Ketones four-membered carbocycles

P-carbon elimination which is facilitated by the release of the ring strain of a four-membered carbocycle via C—C a-bond cleavage, yielding an alkyl-Rh species. The key aryl-Rh intermediate was next delivered by a [1,4]-Rh migration. " Finally, the insertion of the C—Rh bond into the ketone moiety and protonation of the Rh—O bond furnishes the desired substituted indanol products. 

Similarly to cyclopropanes, four-membered carbocyclic compounds undergo oxidative addition to low-valent transition metals to form five-membered metallacycles. Rhodium(I) inserts into C-C bonds next to the carbonyl group of ketones to form a rhodacycloalkanone species [49]. The C-C bond of cyclobutanone was cleaved, even at room temperature, by oxidative addition to a rhodium(I) complex having a PBP pincer ligand [50]. In the case of cyclobutanone 70, catalytic decarbonylation was possible and afforded the alkene 71 and cyclopropane 72 (Scheme 3.40). 

Practicable syntheses of four-, five, and six-membered carbocyclic rings have been achieved by reaction of a,to-di-Grignard reagents with silver(i) salts. Conversion of l,3-bis(chloromethyl)cyclopentane into norbornane was effected in 82% yield, but was the only bridged-ring synthesis reported. Stereospecific cyclic ketone formation using iron(O) compounds has been reviewed. ... 

In view of the wide distribution of the cyclohexanehexols (called inositols or cyclitols) and the importance of one in particular (myo-inositol) to certain bacteria, plants, and perhaps even to warm-blooded animals, the naturally occurring and synthetic compounds of this carbocyclic class have received considerable study. Naturally occurring members include four inositols, monomethyl ethers, a dimethyl ether, monodeoxy derivatives, one dideoxy derivative, a methyl homolog, and deoxy carboxylic acids. Five inositols and many other synthetic members, including ketones (cycloses or inososes), are known. 

---