Novel spiroacetal synthesis via hydroboration of alkynediols

Article abstract of DOI:10.1246/cl.1998.81

Alkynediols were transformed to the corresponding spiroacetals by the sequence of hydroboration with disiamylborane, oxidation of the resulting alkenylboron intermediate with alkaline hydrogen peroxide, and catalytic treatment with p-TsOH. By this transformation, 6-(2-hydroxymethyl)phenyl-3-methyl-5-hexyn-1-ol was converted to spiro[3,4-dihydro-1H-2-benzopyran-3,2′-[4′]methyl[3′,4′, 5′,6′]tetrahydro-2′H-pyran] as a single diastereomer.