An efficient synthesis of functionalized tricyclo[6.3.1.01,6]dodec-4-enes by a stereoselective intramolecular Diels–Alder reaction

Abstract

An efficient and highly stereoselective synthesis of functionalized tricyclo[6.3.1.0^1,6]dodec-4-enes (1c,e,f–h), which would be useful and common synthons for constructing basic carbon frameworks of various kinds of natural products, is described. The key feature of the synthesis was a stereoselective intramolecular Diels–Alder reaction of the cyclohexanone derivatives (10c,e,f–h), which were easily derived from cyclohexanone in 4–5 steps. The whole structure and the stereochemistry of a major cycloadduct (1e) was established by a single-crystal X-ray analysis.