Regiospecific synthesis of 2-substituted 4-methyl-3,6-dihydro-2H-pyrans

The chloroalkylation of 3-halo-2-methyl-1-buten-4-ols was used to synthesize 4,5-dihalo-4-methyl-2-substituted tetrahydropyrans, which were converted regiospecifically to 3,6-dihydropyrans by reaction with magnesium. A similar reaction with zinc dust gave mixtures of 3,6- and 5,6-dihydropyrans.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1189–1193, September, 1985.