“…The condensation of α,β-unsaturated carbonyl compounds with the vinyl ethers of phenols, α,β-naphthols [178,[419][420][421], alcohols of the piperidine, pyridine, and quinoline series (G. G. Skvortsova et al) [178,422], polyfluoroalkanols (N. A. Nedolya, L. L. Dmitrieva) [16,423,424], and also with the mono-and divinyl ethers of diols (A. S. Atavin, V. I. Lavrov, V. K. Stankevich) [36,[425][426][427][428] leads to 3,4-dihydro-2H-pyrans. Involvement of the latter in various reactions with participation of the substituents or dihydropyran ring led to the production of new families of functionalized dihydropyrans [36,427,[429][430][431] and tetrahydropyrans [178].…”