A novel marine natural product, (+)-aureol (1), was efficiently synthesized starting from the cis-fused decalin derivative 4. The synthetic method features borontrifluoride etherate-promoted rearrangement/cyclization reaction of (+)-arenarol (2) to form (+)-aureol (1) with complete stereoselectivity in high yield. (+)-Arenarol (2) was prepared in an alternative and more efficient manner employing