Treatment of Baylis–Hillman adducts with triethyl orthoacetate in the presence of heterogeneous catalysts: a method for the stereoselective synthesis of two different types of trisubstituted alkenes

Baylis–Hillman adducts on treatment with triethyl orthoacetate in the presence of HClO4–SiO2 afford the corresponding allyl ethyl ethers while in the presence of NaHSO4–SiO2 undergo the Johnson–Claisen rearrangement to form ethyl alk-4-enoates. Thus two different types of trisubstituted alkenes are produced in a stereoselective manner using two different hetereogeneous catalysts.