β-Stereospecific hydroboration of 13-epi-pimar-8(14)-enes
Abstract
β-Stereospecific hydroborations of the Δ8(14)-double bond in 13-epi-pimarenes were achieved in the absence of functional groups at C-16 or a double bond at C-15. The reaction carried out on 15,16-dihydrosandaracopimaric derivatives needed more time and a large excess of reagent due to stereochemical restrictions in the transition state.