| Abstract: | In 8- and 9-membered cyclic ketones, transannular interactions of an EtN group or an O atom shift considerably the 17O signal of the carbonyl group to higher fields; S appears to have no such effect. The same ketones show markedly diminished speeds of water addition, compared to simple ketones; this reaction was followed by measuring the rate of oxygen exchange between 17O-labelled ketones and (unenriched) water. Transannular interaction inhibits completely in N-ethyl-azacyclodecane-6-one the exchange reaction, including labelling attemps. |
