1- bicyclo alkane cycloalkanone

Bicyclo[n.l.O]alkan-l-oxyl radicals are fleeting intermediates in homolytic reactions of 2-(halomethyl)cycloalkanones and related radical precursors. Unrearranged 2-methyl-cyclohexanone (19) was obtained from treatment of 2-[(phenylselanyl)methyl]cyclohexanone (18) with tributyltin hydride. ... 

An improved method of thermal ring expansion employs silyl enol ethers as starting materials. The synthetic sequence begins with a cycloalkanone which is converted, via dihalo-cyclopropanation of the silyl enol ether, to a dihalo-1-trimethylsiloxybicyclo[n. 1.0]alkane. Thermolysis of the latter in refluxing benzene affords ring-expanded 2-halocycloalken-2-ones, after elimination of halotrimethylsilane. Alternatively, the same product can be obtained by treatment of the dihalo-l-(trimethylsiloxy)bicyclo[n. 1,0]alkane with hydrochloric acid at room temperature (Table 4).3°.3i... 

It is not essential to use mono- or dihalocyclopropane derivatives. Ring expansion of methylene adducts, i.e. l-(trimethylsiloxy)bicyclo[n.l.O]alkanes 14, can be accomplished with a reagent consisting of iron(III) chloride in pyridine and dimethylformamide. In this process, p-chlorocycloalkanones 15 are the initial products of ring cleavage, but they are most conveniently converted to cycloalkanones 16 by refluxing with sodium acetate in methanol. ... 

One-carbon ring expansion of 2-substituted cycloalkanones 37 (usually / -oxo esters) via transient bicyclo[n. 1.0]alkan-l -oxyl radicals 39 has been extensively exploited as a method of making medium and large ring cycloalkanones 40. " One-carbon ring expansion was also performed with bicyclo[5.3.0]decan-2-ones 41 giving 42 as the product. 

Bicyclo[x.3.0]alkan-l-ols were obtained in moderate to good yields from the same type of reaction when 2-(3-iodopropyl)cycloalkanones were reacted with magnesium in tetrahydrofuran [78] ... 

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