Mechanistic and Exploratory Investigations into the Synthesis of 1,3,5-Triaroylbenzenes from 1-Aryl-2-propyn-1-ones and 1,3,5-Triacetylbenzene from 4-Methoxy-3-buten-2-one by Cyclotrimerization in Hot Water in the Absence of Added Acid or Base
intermediate for the formation of 2, 2′ and the acetophenone derivatives as byproducts. When 4-methoxy-3-buten-2-one (4) was heated in hot pure water without any additive at 150 °C for 30 min, 1,3,5-triacetylbenzene (5) was obtained in an isolated yield of 77% just by removing water by filtering the crystalline product from the cooled reaction mixture. The reaction did not take place in the absence of