A Formal Asymmetric Synthesis of (−)-Epibatidine Using a Highly Diastereoselective Hetero Diels–Alder Reaction

A formal asymmetric synthesis of (−)-epibatidine is reported. The key step of the synthesis is a regio- and diastereoselective cycloaddition of silyloxycyclohexadiene with the acylnitroso dienophile derived from (+)-camphorsultam. The resulting cycloadduct was readily transformed into the N-protected-7-azabicyclo[2.2.1]heptan-2-one derivative which has previously been transformed into (−)-epibatidine.