sentences:  Next, a series of condensation reactions of three acetate units from malonyl-CoA occurs, each proceeding through an acetyl-CoA carbanion derived from malonyl-CoA decarboxylation.This extends the polyketide intermediate.After the generation of a thioester-linked tetraketide, a regiospecific C1,C6 Claisen condensation occurs, forming a new ring system to generate naringenin chalcone.