Di-, tri-, and tetrasubstituted β-lactones are accessible in a one-step procedure by a Reformatskyreaction of phenyl α-bromoalkanoates with ketones or aldehydes at a sacrificial indium anode. With indium powder comparable results are obtained. The yield of β-lactones is significantly lower, if zinc is used instead of indium.
Synthesis of .beta.-Lactones via a Spontaneous Intramolecular Cyclization of O-Lithiated Phenyl .beta.-Hydroxyalkanoates Obtained by Aldolization of Ketones or Aldehydes with Lithium Enolates of Phenyl Esters