A. A. Gevorkyan

MECHANISM OF CYCLOALKYLATION OF ALLYLCARBINOLS BY ALDEHYDES AND KETONES

Das Methallylcarbinol (I) cyclisiert in Gegenwart von katalytischen Mengen Mineralsaure mit Aldehyden und Ketonen (II) zu Tetrahydro- und Dihydropyranen (III) und (IV).

Reaction of 1-halo-3-methyl-2,3-epoxybutanes with secondary amines

Abstract1-Chloro(bromo)-2,3-epoxybutanes react with secondary amines at the C-halogen bond to give amino derivatives in high yields. It was established that under the influence of BF2·OEt3 the latter undergo isomerization to amino ketones, which were also synthesized from 1-bromo-3-methyl-2-butanones.

Reactions of 1-halo-3-methyl-2,3-epoxybutane with alcohols

The reaction of 1-bromo(or chloro)-3-methyl-2,3-epoxybutane with alcohols in the presence of the alkali metal alkoxides leads to the formation of epoxy ethers by direct replacement of the halogen atoms without participation of the epoxide ring.

Addition of carbenes to 4-methyl-5,6-dihydro-2H- and 4-methylenetetrahydropyrans

It is shown that 4-methylenetetrahydropyran adds a methylene group under the conditions of the Simmons-Smith reaction to give 4,4-dimethylenetetrahydropyran. 4-Methyldihydro-2H-pyran and 4-methylenetetrahydropyran add dichlorocarbene in the presence of a catalyst, viz., triethylbenzylammonium chloride, to give two-ring adducts. It is shown that the adducts can be converted to ketals by refluxing for many hours with alcoholic alkali. The structures of the compounds obtained were established by gas-liquid chromatography and PMR and IR spectroscopy.