Thermodecarbonylation of α-substituted cycloalkanones: a convenient one-carbon ring contraction method

A new and very convenient one-carbon ring contraction method is reported. Pyrolysis of α-substituted cycloalkanones at 600–650 °C under flow conditions produces the ring contracted compounds under loss of carbon monoxide. Substrates varying in ring size and nature of the α-substituent have been investigated.