Streamlined Synthesis of Triamantane from Readily Available Starting Materials

Abstract

As molecular fragments of diamond, diamondoids represent a unique class of cage hydrocarbons with extreme rigidity, stability, and ideal biocompatibility. Together with adamantane and diamantane, triamantane belongs to the lower diamondoids, which are favorable precursors for a diversity of applications in medicinal chemistry and materials science, or as gateway to synthetic higher diamondoids. After employing triamantane in the synthesis of skew-tetramantane, we now report a practical synthetic procedure based on McKervey's variation of Schleyer's stabilomeric synthesis and the versatile chemistry enabled by the norbornadiene dimer Binor-S. After optimization, a Binor-S rearrangement and subsequent Diels–Alder reaction with a readily available solution of butadiene allowed to prepare triamantane in synthetically meaningful yields on a tens-of-grams scale. Building on the concept of stabilomeric synthesis, streamlining the route to triamantane provides an alternative to its isolation from fossil fuels and enables diverse applications of triamantane or the synthesis of higher diamondoids, such as skew-tetramantane.