One-Atom Expansions

Base-induced one-carbon homologations of cyclohexanones have found utility in the preparation of cycloheptanones because they are based on often readily available six-membered rings (Eqs. 16 and 

Other reactive intermediates have been used to effect one-atom expansions of six-membered rings. These approaches include the use of radicals (Eq. 18) and photolysis (Eq. 19), the latter involving 

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