HYDROBORATION-OXIDATION OF ABIETIC ACID

Monohydroboration-oxidation of abiotic acid and methyl abietate with both diborane and t-2,3-dimethylbutyl-borane leads to preferential attack on the 7,8-double bond to give 7-hydroxy-8(14)-enes, e.g., (IIIa). Dihydroboration- oxidation with these reagents yields mainly the 7β.14β-dihydroxy derivatives, e.g.. (XIXa), with smaller amounts of the 7α,14α- dihydroxy-compounds and a third 7,14-diol of unknown stereochemistry. The dihydroboration reactions are of interest, since it is shown that at least one of the products is derived by migration of the 13,14-double bond of abietic acid to the 8,14-position during hydroboration. Some reactions of the hydroxyabietic acid derivatives are described.